Final Flashcards

Question

dinosaurs couldn’t chew like mammals cuz didn’t have those grinding teeth-so how did they process plant material? hadrosaurs:

Answer 1

cranial kinesis

Answer 2

-hadrosaurs developed whole new way to chew-mammals can chow cuz can move jaws from side to side-dinos couldn’t do this motion allowed by your lower jaw-took advantage of their cranial kinesis-our only joint is at jaw-dinos have kinetic skulls so all kinds of joints up in head-as the lower teeth come up, hit upper teeth and push them out, then there’s a little point so cheeks at the top flap out-that motions causes grinding-so when chew, not side to side, but cheeks going in and out as chew

Answer 3

predentary bone

Answer 4

-basically had little beak for helping tear off things and bring into mouth-nip off plant material and pull into mouth-nail like keratin material in front of mouth instead of teeth-modern horned mammal has this and looks like some dinos had it too

Answer 5

- need cheeks to chew-food will spill out of mouth without cheeks - so dinos that chew probably had cheeks, while carnivore dinos probably didn’t-no cheeks-cuz no processing in mouth-doesn’t need cheeks-just swallow whole

Answer 6

- easy - Just tear off a chunk and swallow - Meat is relatively easy to digest-got lots of enzymes that can break down meat easily - Requires blade-like teeth for tearing & cutting flesh - Also, simple conical teeth for puncturing/ killing

Answer 7

T rex had giant teeth-probably for just killing, didn’t do much chewing-probably didn’t even do much tearing with teeth-just yanking into mouth then swallow whole

Answer 8

- side of jaw - raspy tongue cleans meat from bone - kill with front teeth, blade like teeth in back fro cutting up chunks to eat

Answer 9

- slicing, cutting | - cuz don’t swallow things whole-not doing much chewing though if carnivore

Answer 10

Tooth Serrations - Serrations help hold what is being cut in place - Also help with keeping the edge sharp - Can also hold bacteria only some groups-some debate about it (e.g., Komodo dragon) - theropod teeth serrated

Answer 11

- hyena jaw more scissor like, good for tearing-like sideways V - rabbit jaw-2 Ls on their backs, connect at bottom of L-having jaw above the tooth bone-allowed teeth to meet at same time-good for grinding

Answer 12

- in herbivores, like warthogs | - allow to do side to side motion-emphasize those muscles so can do side to side grinding

Answer 13

- this is where things get complicated-sometimes see herbivores with big pointy teeth - usually when see in herbivores-some kind of sexual selection-male warthog, uses big teeth to show how sexy is, attract mates

Answer 14

- same thing as before, first type of jaw (seen in T rex) is good for meat eating (like V) - second one (2 Ls-but now like lying on so small part of L faces down on left side-so joint below bend)-herbivores-instead of jaw bone being above tooth growth, it’s below-but effect is the same-teeth will meet at the same time to do grinding

Answer 15

- Fish-eaters tend to have long, thin snouts with homodont, pointed teeth for catching fast fish-fish are really fast so need jaw that will close really fast and has little tiny teeth to grab onto them - long snout - some dinos were probably piscivores as well-ate fish

Answer 16

- think ate fish cuz adaptations/characteristics similar to others that did - pterosaurs-not dinos but closely related - some specialized dinos needed specialized teeth-other types of specialized teeth or having no teeth-these are just examples of how teeth can show diet and how ate

Answer 17

- meaning how got energy, what did they use it for - Cold-blooded vs. Warm-blooded Dinosaurs-this is argued-most say somewhat warm-blooded, but neither of these terms are very good-better terms to describe it, also this is too dichotic-2 poles-many animals, like dinos, are more in the middle

Answer 18

- Endotherms – generate heat internally - Ectotherms – need external sources of heat - Homeotherms – maintain constant internal body temperature - Poikilotherms – body temperature varies, usually in relation to the environment-goes up and down depending on what’s going on in environment - (most) Mammals and Birds – endothermic homeotherms-generate heat internally, use to keep relatively constant body temperature - (most) modern “reptiles” – ectothermic poikilotherms

Answer 19

generate heat internally

Answer 20

need external sources of heat

Answer 21

maintain constant internal body temperature

Answer 22

body temperature varies, usually in relation to the environment-goes up and down depending on what’s going on in environment

Answer 23

- (most) Mammals and Birds-but also some fish and insects (exception)-and bats + some bird endothermic poikilotherms (exception) - generate heat internally, use to keep relatively constant body temperature

Answer 24

- (most) modern “reptiles”-except some large reptiles (exception), which are ectothermic homeotherms - most fish, amphibians, reptiles, and most invertebrates-body changes due to environment, external sources of heat from environment

Answer 25

- Bats and some birds endothermic poikilotherms (also hibernating mammals) - Some fish and insects endothermic homeotherms - Some large reptiles ectothermic homeotherms

Answer 26

No way is better than another-all about tradeoffs, each has own benefits and costs

Answer 27

– Sustained activity – Active at night – Adaptation to cold environments

Answer 28

– Requires LOTS of food - 10-30x similarly sized ectotherms | – Not efficient at small body sizes…why? (has to do with surface area/volume ratio)

Answer 29

– Adaptation to hot environments | – Need little food

Answer 30

(primitive condition-but that's okay) – Capable of only short bursts of activity – Limited ability to be active at night

Answer 31

-Surface Area/Volume relationship

Answer 32

- if small, most of matter is closer to the surface-less volume relative to surface area-high surface area to volume ratio - if bigger, stuff in middle that’s farther from the edges/outside-a lot more volume relative to the surface area-low surface area to volume ratio - so larger animals tend to have a lower SA:V ratio/low SA compared to volume compared to that of smaller animals

Answer 33

-The surface area of an animal is where it exchanges heat with the environment-small endotherms have a problem retaining heat cuz high SA to V ratio-big endotherms have problems dumping heat-may overheat-so big animals like elephants tend to have big radiators-like big ears on elephants-to increase SA

Answer 34

retaining heat (because they have high SA/V)

Answer 35

dumping excess heat (because they have low SA/V)

Answer 36

no smaller than a few inches

Answer 37

-doesn't matter if ectotherm-actually better to smaller-can get really tiny

Answer 38

- Large animals retain heat | - So large ectotherms can be homeothermic…

Answer 39

- If they were endotherms did they overheat? - If they were ectotherms were they gigantotherms? - what were dinosaurs?! Ectotherms? Gigantotherms? Endotherms? - Were they all the same?! - this is why there’s such big debate about dinosaur endo vs. ectothermy - cladogram doesn’t really help here-ectotherms primitive trait-endothermy evolved somewhere-but we don’t know where-the 2 living groups that are on either side of the dinos-birds and crocs-are different-so that doesn’t really help us. Could mean endothermy evolved on before or after dinos

Answer 40

- Cardiopulmonary evidence – hearts & lungs - Insulation - Bone and growth rates - Neurophysiology – relative brain size - Isotopic evidence - Skull features – turbinates - Posture – bipedality & running - Biogeographic Distribution – Do we find dinosaurs in cold places?

Answer 41

-what’s interesting is that hole area-people think there may have been a heart there-think can even see chambers within the heart-know all modern endotherms have a 4 chambered heart-4 chambered heart tends to be much more efficient in terms of pumping oxygenated blood around-mammals and birds have a 4 chambered heart-but it turns out that doesn’t help us very much, cuz it turns out crocs also had a 4 chambered heart-so the fact that they found a 4 chambered heart in that dino isn’t that surprising-this bracket below tells us that dinos probably had a 4 chambered heart -now there’s some question about whether it’s the same 4 chambered heart in crocs and birds, whether it’s homologous, or if it’s an analagous thing-did they evolve them convergently or separately-some debate about this-turns out 4 chambered hearts in crocs are a little different and mostly used less because of their efficiency in pumping, more cuz of thier efficiency for diving, so crocs have a special shunt that they use in their blood supply and circulatory system when they’re diving to preserve oxygen and things like that-the point here is that the fact that finding the 4 chambered heart in this dino isn’t particularly surprising-it may hint that they are endotherms, but the fact that crocs have them tell us that this isn’t particularly conclusive

Answer 42

Bird Lungs: - Bird have a number of air sacs connecting to their respiratory pathway -basically just dead spaces of air-there isn’t oxygen exchange happening in them-that only happens in the lungs-but basically these air sacs that are connected to the respiratory sac that extend into parts of their skeleton and parts of their axial skeleton and things like that that kind of fill up their body-fill up their spaces with these air sacs - This (these air sacs) allows for more efficient one-way airflow during breathing - what happens is they breathe in, air goes into air sacs, no oxygen exchange happens, and then on the next breath that air moves across the lungs, and then on the next breath it gets moved out-takes them 2 full cycles of respiration to get air in and out-this allows for very efficient oxygen exchange when air goes across the lungs-in mammals, breathe air in, goes into lungs, sits there for a while doing nothing-in this case, the air is always moving through the lungs, and that actually allowed for more efficient oxygen exchange (called countercurrent flow)-birds need this-flying is costly in terms of oxygen-need oxygen to fuel muscles used for flying - mammals and birds (endotherms) have high oxygen demands, birds even more so than mammals - if were to see these kinds of air sacs in dinos, would imply there’s some sort of high oxygen demand - It seems that some dinosaurs had air sacs too, similar to modern birds - air sacs in sauropod vertebra-probably filled with air-a number of air sacs wrapped around vertebrae - the fact that dinos had air sacs speaks to the fact that maybe they were endotherms, like birds and mammals are

Answer 43

- more - have higher respiration rates-ectotherms like snakes don’t breathe as often-cuz metabolism relatively low-main reason breathe in oxygen is to help you break down food taking it-so cuz don’t eat that much food don’t need as much oxygen-mammals and birds on the other hand have high oxygen demands, birds even more so than mammals

Answer 44

- have 1 way breathing too - but don’t do it the same as birds-like the way their 4 chambered hearts aren’t the same as birds-do it slightly differently, has more to do with diving in crocodiles-so that tells us that maybe the air sacs in dinos weren’t for efficient breathing-this study is only a couple of years old-the fact that we’re just finding this out about crocs points out that there’s a lot of stuff out there about animals that we still don’t know-lots of work to still be done even about living animals

Answer 45

- Only modern endotherms have insulation (something to insulate their bodies) - Birds have feathers - Mammals have fur - It seems that many dinosaurs had feathers too… maybe not as many as modern birds but just the fact that dinos had any insulation at all points to dinos being endotherms-cuz helps you keep in the heat that you’re generating - we find more and more evidence for feathered dinos every year

Answer 46

- our bones are not solid-are hollow on the inside-solid part on the outside called compact bone-and then on the inside the bone is either hollow or has spongy looking bone-it’s within this space (in hollow part or holes in sponge) where you have marrow - we’re gonna be looking more at the compact bone-the diff between endotherms and ectotherms of their compact outside area of bone - most of bones in body start off with cartilage model-later gets replaced by bone, first shaft then ends-then growth plate between the shaft and ends of the bone-that’s how bones grow - the growth plate is key-limits how big you can grow-so we have a determinate growth - reptiles on the other hand have what’s called indeterminate growth

Answer 47

-endotherms tend to have determinate growth and ectotherms tend to have indeterminate growth

Answer 48

-predetermined how tall we can be when born-nutrition can affect this but for the most part mammals and birds have determinate growth

Answer 49

growth happens in similar way, but no growth plan-body just keeps adding more and more bone on the outside of a bone, bone keeps getting bigger and bigger-reptile can grow indefinitely-growth rate slows down over time, but never stops

Answer 50

- the other thing we want to look at inside the bone is look at that compact bone in more detail - compact bone actually isn’t solid, is only mostly solid-has some blood vessels running through it-because bone is a living material-it grows, it has cells that are constantly remodeling, it turns out 5-10 years from now all of your bone will be diff from the bone you have now, because slowly replaced with new bone-so it’s highly revascular, has lots of blood vessels-and it’s always being remodeled, reworked-reworking is often unorganized-if you look at it up close, see bulls-eye like structure, called osteon-in the middle of it is a blood vessel/where the blood vessels go called the haversian canal-and all the dark parts are where a bone cell lives (what’s called a osteocyte)-they’re constantly reworking bones-break down osteons, rebuild new osteons-constantly rebuilding that bulls-eye structure-and they don’t do it with a whole lot of organization-sometimes mammalian bone is called “woven” because it’s disorganized like this-with lots of layers all over each other and reworked

Answer 51

- similar to mammalian bone | - same reworked, woven bone-not organized, random placement of osteocytes-tends to be relatively random

Answer 52

- another thing we see in bones, especially those of ecotherms - definition: Characterize times of slowed/stopped growth - ectotherms are constantly laying down bone on the outside so they can grow indeterminately-that growth doesn’t happen continuously-grows for a little, then stops for a while, then grows again, then sits for a while, etc. - can see this stopping and starting in what are called lines of arrested growth - tend to be on annual cycles-when it gets cold ectotherms, generate their heat internally, so they tend to stop growing because they can’t put their resources/energy into growing because they’re putting energy into staying warm-so they don’t grow in the winter months-then they grow when it gets warm out - because lines of arrested growth have to do with changes in temperature, tend to be seen more in ectotherm - Similar to tree rings-grow in spurts then stop-looking at them gives hint to past/climate of past

Answer 53

- dinosaur bones, when you look at them in crossection, are often woven like bird and mammal bones, with disorganized growth-but, they also sometimes have LAGs, which speaks to some sort of arrested growth that’s going on-a little equivocal-bones that sometimes look like mammal and bird bones, but also sometimes like reptiles - but there’s another twist to this story: it turns out that sometimes mammals get LAGs too-certain mammals, esp those who live in environments that are highly variable, often get these LAGs-usually looks random and woven but every once in a while get some LAGs-this is similar to dinos-so maybe the fact that dinos have these LAGs is not that big of deal, doesn’t say much about endothermy vs. ectothermy-so this bone growth stuff is a little unclear

Answer 54

some mammals get LAGs too

Answer 55

- tend to have a 3 part growth curve: - Slow growth as infants and toddlers - Fast growth as juveniles and adolescents - Slow growth (or stopping) as adults

Answer 56

-tend to have a relatively constant growth rate-does slow down as gets older but don’t have this 3 part growth curve

Answer 57

- Dinos had a 3 part growth curve, especially the biggest ones - They also grew at rates faster than birds or mammals-the large ones are putting on 10s of kg a day (during their time of highest growth rate)-literally 20 lbs a day-pretty extreme-the fact that they’re extreme is more similar to endotherms than ectotherms-some mammals do this, like whales - Large sauropods: 20 kg/day (similar to whales) - Large theropods: 2 kg/day (similar to birds & mammals) - Small-mid-sized: 1-800 g/day

Answer 58

- Large sauropods: 50 yrs - Large theropods: 30 yrs - Small to mid-sized: 7-15 yrs - Smallest: 3-4 yrs

Answer 59

-All of this is similar to modern endotherms-pretty similar to modern mammals if scale them up to these sizes-the fact that dinosaur growth compared to life spans are similar speaks to this

Answer 60

- Ratio of brain size to body size - brains are metabolically expensive, meaning that it takes a lot of energy and oxygen to keep brains going-so only animals with access to a lot of energy and oxygen have large brains - one way we measure the size of brains is not absolute size, cuz then would say whale have bigger brains than humans-what we use is relative brain size-ratio of brain size to body size-called the encephalization quotient

Answer 61

- high-because brains are expensive | - humans have a very big brain for their body size

Answer 62

- Dinosaurs show a range of encephalization quotient, with some similar to modern birds - some really small brains-but some ornithopods and some meat-eating dinos have pretty big brains, similar to birds

Answer 63

- Different isotopes have different weights (Why?) has to do with the fact that they basically have diff number of neutrons-C 12 and C 14 act the same chemically cuz have the same number of protons-but have diff numbers of neutrons so C14 is heavier-neutrons don’t have anything to do with chemicals to C14 acts just like C12-could make CO2 out of C14, carbon in bodies out of it, and so on and so forth. It’s just a little heavier. - Lighter isotopes are preferred in most chemical reactions though-it’s easier to move them around because they’re lighter-chemical reactions driven by heat, the heat tends to move things that are lighter rather than heavier-lighter tend to be more incorporated into chemical reactions - At higher temperatures this difference between the 2 becomes less -at low temperatures the C12 is more preferred than the C14-but as get higher and higher temperature the difference between the 2 doesn’t matter as much -at higher temps, the diff of weight doesn’t matter as much, because there’s enough heat to move whatever you want around - use this to tell relative body temps on species (temp at extremities vs. core)

Answer 64

-Extremities on the body (e.g., limbs and tails) will be colder in ectotherms-lizards get very cold hands and feet-keep whatever heat they’ve got in their core-what this means is that there’s less of a diff in temperature between the core of an ectotherm, like you, and its fingertips-in an ectotherm, there’s a big diff in temp between these 2 places-this means basically the diff in isotope usage between the extremities won’t vary very much because the temperature’s pretty similar-but in ectotherms huge diff in isotope usage between core and extremities because extremities so much colder so harder to move heavier isotopes around -large modern lizards (like kimodo dragon) tend to have bigger differences between tail/extremities and core than dinos-dino differences in temp between extremities and core more comparable to mammals (this is all relative, not absolute temps)

Answer 65

(like kimodo dragon) tend to have bigger differences between tail/extremities and core than dinos

Answer 66

dino differences in temp between extremities and core more comparable to mammals-not as large differences as lizards

Answer 67

-Uses “clumping” of isotopes at different temperatures-when they do this and look at dinos to find abs temp-looks like dinos had relatively high body temps-similar to endotherms

Answer 68

- Mammals and birds have unique structures in their nose, the turbinates that make their breathing more efficient -little bony structures in the nose, covered in epiphelium, covered in tissue, that makes a bunch of snot-it also has a lot of blood vessels in it - what happens is, as the animal breathes in, cold air from outside goes across those turbinates that are covered in snot and picks up moisture and heat, and that in turn goes down to the lungs-lungs better at getting oxygen out of warm moist air-when mammals breathe, breathe a lot, high respiration rate,want to get as much oxygen as possible, so wanna do this is the most efficient way-this way gets more oxygen, is very efficient-helps maintain heat and moisture - don’t want to lose all that moisture and heat, so what happens is when the air goes back out, that air dumps its heat and dump its moisture onto the turbinates, then just air is breathed out and it’s relatively cool-creature conserves that heat and moisture - animals that run a lot (pursuit predators not pounce predators-chase their prey down) have more complex turbinates cuz need to be more efficient in breathing

Answer 69

- what happens is, as the animal breathes in, cold air from outside goes across those turbinates that are covered in snot and picks up moisture and heat, and that in turn goes down to the lungs-lungs better at getting oxygen out of warm moist air-when mammals breathe, breathe a lot, high respiration rate,want to get as much oxygen as possible, so wanna do this is the most efficient way-this way gets more oxygen, is very efficient-helps maintain heat and moisture - relatively cool, dry air passes over moist, warm turbinates and is heated and saturated with water

Answer 70

yes, except they’re pretty little one-3 on each side, look like little commas-not as cool and intricate as dino ones

Answer 71

- don’t want to lose all that moisture and heat, so what happens is when the air goes back out, that air dumps its heat and dump its moisture onto the turbinates, then just air is breathed out and it’s relatively cool-creature conserves that heat and moisture - warm, most air passes over cooler, drier turbinates and transfers heat and moisture to their surface

Answer 72

more complex turbinates, cuz need to be more efficient in breathing

Answer 73

1) Condition incoming air 2) Conserve heat 3) Conserve water Because: High ventilation rates* in endotherms create a water and heat conservation problem *Ventilation rate = breaths/minute

Answer 74

- Turbinates don’t fossilize well-tend to be broken in fossils-hard to find specimens that still have these specimens inside nose - Use nasal volume (how big it is) as a proxy for how many turbines in it - dinos fall on reptile line-so probably did not have turbinates, which is something we associate with endotherms-mammals have them, and birds do too, but cartilaginous (made of cartilage) in birds-ectotherms don’t have them-dinos don’t have them, except then new study - study from about 5 years ago, actually think they did have turbinates-did same sort of CT scans across the nose-did some modeling-think dinos did have at least very simple sorts of turbinates-the evidence is a little unclear, just like everything else so far

Answer 75

- lizards are sprawled, arms out on sides-runs side to side - lizards, when run, run side to side-air gets compressed, pushing air from 1 lung to another (expanding) moves from one side to the other-instead of air moving in and out of mouths, moving back and forth and side to side - lizards, if chase them, eventually slow down, cuz used all their heat/energy-but also because can’t breathe well while running-can’t get oxygen in while they’re running

Answer 76

-have upright posture with their legs not on their sides but underneath them-legs run underneath body (like mammals)

Answer 77

- have upright posture with their legs not on their sides but underneath them-legs run underneath body-for 4 legged mammals - upright posture allows mammals to time their breathing with their running - mammals, with legs beneath them, can actually time breathing and moving legs/running together-mammal takes a big step forward, breathes in, then breathes out-can time this-expands chest, breathe in-compressed chest-then breathe out-can time those things together-remember mammals use a lot of oxygen-so if can use oxygen more efficiently, means can run longer distances, run more efficiently - mammals can breathe while running-this has to do with this endothermy

Answer 78

-crocodilians and mammal-like reptiles somewhere in between, have semi-sprawling gait-you might expect that since midground between this and that-crocs a little weird, a little diff, peculiar

Answer 79

-dinos, birds, and humans are diff cuz they’re bipedal-moving just on hindlimbs-not doing this sort of thing

Answer 80

- there still is a sort of timing of breathing to walking, even if only walking on 2 limbs-but a little diff - the fact that dinos walk upright, have limbs beneath them, shows they’re more like endotherms than ectotherms

Answer 81

- Dinosaurs did live near the poles-like Antarctica - Modern ectotherms don’t-don’t tend to get ectotherms near the poles-can’t absorb enough heat - BUT, the Mesozoic was a much warmer time - so maybe the fact that they lived at poles doesn’t mean too much - Maybe dinosaurs migrated-maybe what they did to avoid being too cold was just keep moving to the warmest places - but still, the fact that we find dinos at the poles is pretty interesting-and looks like some dinos lived at the poles year round, didn’t migrate-even if it was a warmer time, this is just a colder area than the equator-shows that maybe dinos could handle the cold-this could speak towards endothermy

Answer 82

-basically can figure out temps by looking at isotopes-if look at isotopes across one tooth of dino, can estimate what temp living in-what graph shows is what map shows-looks like some dinos migrated, during summer go to mountains, then down to plains when colder-so they did some migration-modern mammals do this-so maybe what they did to avoid being too cold was just keep moving to the warmest places

Answer 83

- endo - Dinosaurs have the same predator prey ratios as mammals-1 carnivore for every 10 herbivores in modern endothermic ecosystems-in ectothermic ecosystems, a little diff, don’t need as many herbivores to support a carnivore cuz their energy levels aren’t as high

Answer 84

- endo - Dinosaurs have 4-chambered heart and lung air sacs like birds, and may have had one-way airflow-this evidence is a little bit equivocal cuz of crocodiles being a little peculiar, but still points to endothermy

Answer 85

- endo | - Dinosaurs had insulating feathers, like fur or bird feathers

Answer 86

- endo OR ecto - Dinosaurs have bone characters like mammals/bird with complex growth, but also show LAGs-this is more equivocal-so endo or ecto-but tends more towards endo

Answer 87

- ecto - Most dinosaurs have small brains for their body size, although some are as large as birds/mammals -could probably argue endo or ecto

Answer 88

- endo - Dinosaurs have inferred temperatures like birds/mammals and little difference between core and extremities (also like birds/ mammals)

Answer 89

- endo or ecto | - Dinosaurs may have had turbinates like birds/mammals do-but unclear

Answer 90

- endo | - Dinosaurs have non-sprawling posture like birds/mammals

Answer 91

- endo | - Dinosaurs lived in cold environments (poles and mountains) although may have migrated-but some didn’t

Answer 92

- a lot of this evidence is equivocal-evidence for both - can we give a definitive answer? - maybe we’re asking the wrong question-maybe dinos did something totally different - that’s what’s why we’re getting such weird answers when we try to answer the question this way-basically that’s what the Goldilocks Hypothesis is all about

Answer 93

- Animals can put energy into two diff things: maintenance (renewing cells, generating heat, finding food) or production (growth, reproduction, fat storage) - can put some of energy into maintenance (day to day life things) or could put energy into production (the extra stuff-getting bigger, having offspring, etc) - ectotherms and endotherms apportion energy differently - ectotherms: 60% on maintanance, 40% on production - endotherms: 97% on maintenance, 3% on production - remember, being an endotherm is costly-most of energy goes into maintenance cuz have to maintain energy levels, maintain internal heat-costly-so endothermy not necessarily the best strategy as we often believe - ectotherms tend to be pretty even in spreading energy between maintenance and production-can spend more energy on growth than endotherms, that’s why they have indeterminate growth, unlike endotherms - what the Goldilocks hypothesis is, is that it says dinos were somewhere in between-not endothermic or ectothermic-but mesothermic

Answer 94

- dinos somewhere in between endotherms and ectotherms-They had intermediate metabolic rates, but burned energy like ectotherms (i.e., put relatively more energy into production) - So, they could more energy into growth - Remember, dinosaurs got bigger over time (Cope’s Rule) and probably were gigantothermic (meaning that although they didn’t generate their heat internally, they had a relatively constant body temp, just because they were big) - what’s driving this growth in size is the evolutionary arms race (Red Queen Hypothesis-prey get bigger so predators get bigger so prey gets bigger and so on) - ectotherms put more energy into production but tend to have a smaller pool of energy to draw from-just cuz they’re eating less, getting less energy in general - endotherms have a large energy pool but put little of it into production-most of it gets put into maintenance - dinos were somewhere in middle-this is why its the Goldilocks hypothesis-large pool of energy, and put lots of it into production-burn energy like an ectotherm, but have an energy pool like an endotherm-basically what this means is that dinos were doing something totally different (from modern species)-we just don’t have many good models for it today -the way it’s sometimes described as they can raise their body temp but they don’t defend it

Answer 95

can put more energy into production, but have a smaller pool of energy to draw from

Answer 96

have a large pool of energy, and can put lots of it into production (<--just right)

Answer 97

have a larger energy pool, but can put little of it into production, because their maintenance is so costly

Answer 98

- Raise their body temperature, but don’t ‘defend it’ -put energy into maintenance and increasing body temp, and then they become gigantothermic, and then they don’t defend it, meaning they don’t use energy to maintain a high body temp - one of the lines of evidence for this comes from growth rates-rate in the middle between endo and ectotherms (for mesotherms and dinos) - dinos fall in middle ground here between ectotherms and endotherms

Answer 99

- turns out there;s a few animals that fall in between that have this mesothermic body heat thing (examples below) - Modern examples: tuna, echidna, sea turtles - tend to have this metabolic middle ground-between endotherms and ectotherms-and some modern species have this too but not many-maybe dinos were the only ones filling up this space for a while, back in the mesozoic

Answer 100

- you become fully endothermic - This may have happened to some lineages of theropods - One line of evidence of this– they’re the main group to develop feathers -all dinos have some kind of featherlike structure but theropods do it to the extreme - Also, some theropods become herbivorous – more energy at lower tropic levels, in plants - And there are no giants in these lineages -so there’s lineages that lead to birds don’t get very big - And some become birds… - May also explain why there are no small dinosaurs (in other lineages) or marine dinosaurs (because they couldn’t do that without going over the line and becoming endothermic)

Answer 101

- were probably a mix of ecotherms and endotherms and many of them probably fell in between - May have changed their metabolic as they grew-huge dinos start out really small-maybe were endothermic as younger, became ectothermic and gigantothermic as got older - Some taxa were probably more to one end or the other… - so “are dinos ecto or endothermic?” is not a good question - there is no good answer - the answer is that they’re somewhere in between-they’re in between

Answer 102

(not sure if need to know for final) - Born in England, mother died when he was 8, father physician, out on house calls, raised by older sisters - lived off his father’s money until he made him get a job - went to Edinburgh University to become a doctor-fell in love with natural history-met some botanists and geologists-decided didn’t want to be a doctor - trained to be a parson at Cambridge-a country priest-less formal than what we think of as priests now-priest that local people would go to, hold small services - this was a good job for someone of his (high) class-something that kids had nothing to do, what they did-but while he was training, he got asked to go on a voyage on the Beagle as a naturalist (to keep captain company mostly, since captain was high class and didn’t want to socialize w low class sailors-and do some natural history stuff)-2nd choice, 1st couldn’t go-Beagle was a ship of the navy, travelled the world, map coastline of south america-important strategically cuz England had holdings there - Darwin did a lot on the ship though-get off boat, hire guide, take a mule or horse and meet boat farther down coast cuz got seasick-made a lot of observations during this - while on this trip got kinda famous-sending reports back to newspapers in England-when came back was pretty famous cuz he had a column, people reading it - publishes book when he gets back, basically lives the rest of his life as an author - marries cousin Emma-not uncommon at the time

Answer 103

-1839-publishes first book, on the Beagle voyage -also marries his first cousin, Emma Edgewood -1840-develops his mysterious illness-people have debated what this illness was-due to stress about thinking of publishing his theory of evolution? tropical disease picked up on his trip? psychosomatic? he spent the rest of his life mostly at home sick -1843 moves to Dorn house with Emma-lived the rest of their lives there-had 11 children, 2 died in infancy -1851-daughter Annie (favorite, helped him with science stuff) dies-huge event in Darwin’s life-changed his outlook on life, probably views on religion -1858-presents an abstract on the Origin of Species -1859-publishes the full book-later goes through 6 editions -does lots of work and publishing from home after this 1882-died-friends and supporters (esp Thomas Huxley) petitioned to have him buried in Westminster Abbey-buried with honor there

Answer 104

- published 19 books - talked about animals he found on his trip on the Beagle - published 6 version of Origin of Species - did not mention man in this book-but later published a book called the Descent of Man-more of his ideas on human evolution - published books on biology, barnacles, animals, scientific inquiry, etc.

Answer 105

- a diverse group of bipedal saurischian dinosaurs - birds are actually the descendants of small nonflying theropods - The most popular group of dinosaurs - Both with the public and paleontologists – 40% of all dinosaur species named - Most debated group in dinosaur studies - Extremely diverse taxonomically and ecologically – But rare in the fossil record (10-20% of finds) -so amount found disproportionate to how many in ecosystem - Widely distributed – present at every dinosaur fossil locality

Answer 106

- Carnivores!!! - Most are carnivorous with recurved, pointed teeth, some with serrations - Characterized by intramandibular joint

Answer 107

- Pneumatized Skull - Lots of air spaces to lighten the skull - Both between and within bones - Seen in the post-cranial skeleton as well - very small brain-most of the space in skull filled w air - air sacs - Similar to human sinuses-we have air sacs as well, called our sinuses

Answer 108

- Trend toward larger brains (in relation to body) -in some | - Some later taxa have EQs similar to birds

Answer 109

- Enhanced hearing and smell | - Stereoscopic Vision

Answer 110

-when look T rex head on-eyes pointing towards you-means field of view of the 2 eyes cross over each other-gives depth perception (=the diff in position between your 2 eyes that tells you position)-many predators have this cuz helps catch prey-prey usually has eyes more on sides, so get wide range of vision to detect prey

Answer 111

Bipedal - small and bipedal-many dinos evolved to walk on 4 legs later-but these guys stuck w 2 legs - Only group to retain full obligate bipedality - Much longer hindlimbs than forelimbs * - Digitigrade * - Reduction in digits I & V * - 5 sacral vertebrae * - Stiffened tails * * =Running (Cursoriality)

Answer 112

- Loss/reduction of digits IV & V as all dinos do(and sometimes III) - Some opposability of digit I -can kind of grasp - some dinos had really short arms-but short limbs were still strong! may have been used for something diff-to hold down prey? mating? unclear-but although small, weren’t weak

Answer 113

Huge Diversity in Size - Tyrannosaurus rex (6000kg) to Mircoraptor (1kg) - If you include modern birds the difference from smallest (hummingbird) to largest is 5,000,000x ! - largest terrestrial carnivore today is the polar bear, which is 10x smaller than T Rex - T. rex largest terrestrial carnivore to have ever lived! in terms of mass - Other theropods may have been taller than T. rex, but none heavier (probably) - but not all theropods were big

Answer 114

- other things around that weren’t theropods that were eating meat-more of them than theropods-and even out of theropods, most of them were small theropods - dryadissector=another small predator that was common

Answer 115

- South American - Mid-Late Triassic (230Ma) - Possibly basal theropods - Possibly basal dinosaurs - Defined by lack of characters

Answer 116

- Mainly small, North American & African forms - Late Triassic and Jurassic - Coelophysis-most numerous dinosaur fossil - Ghost Ranch Site, NM - all traveling in herd, killed in flood, lots of fossils in one area-La Brea tar pits?

Answer 117

bones in animals found of some small organisms-originally thought these were bones of small Coelophysids -so were cannibals, older eating the young-some species do this, territorial thing, take over pack and eat young so know any future young are its own-maybe the case here-but now found that probably weren’t cannibals, were eating some other small animals

Answer 118

``` -Primarily Gondwanan – S.Amer, Africa, Madagascar, India, maybe Europe – Biogeographic implications -Mostly Cretaceous -Some have “headgear” ```

Answer 119

- Horned dinosaurs - Mainly Gondwanan - Mainly Cretaceous

Answer 120

- name means “Stiff Tail” - Further reduced digits - Loss of IV & V (as all dinos) and III reduced/lost (diff from other dinos) - More pneumatized heads-extra skull hole-in front of antorbital fenestra - Pubic foot - Muscle attachment for muscles that move the tail

Answer 121

- Mainly Cretaceous - Large, but lightly built - Some have sail-backs – Why? - Some piscivorous (long thin snouts with lots of little teeth-to catch fish)& semiaquatic (spent some time in the water - Includes Megalosaurus - long thin snouts with lots of little teeth - Recent finds of a more complete skeleton - Some now think they were semi-aquatic -thicker ribs-use to help them sink in the water-these guys had some ribs that looked similar to that-seen in modern animals like manatees-this is debated

Answer 122

- Thermoregulation?-maybe these guys were still ectothermic - Cooling? - Heat storage? like backpack to store heat and fat - Display? maybe colorful to attract mates - Support? tendon that runs all along spine and to head-helps hold head up-patterns along spine like that make easier to hold head up, with the help of the tendon

Answer 123

-Dinosaurs more similar to mammals with humps for fat or support than to sail-backed mammal-like reptiles

Answer 124

- Middle Jurassic to late Cretaceous - Laurasian - Some atain large sizes, but most are medium sized

Answer 125

-Central UT -Species Counts: – 44 Allosaurus – 6 other theropods – 9 sauropods – 5 ornithopods – 4 Stegosaurus -Predator Trap! Locality was in sticky mud near a river bank-know cuz 10x more carnivorous than herbivores (looking at species found above)-should be other way around because of 10% energy transfer up pyramid-we talked about this before-prey got stuck, predators thought easy catch, went in and got caught too, kept happening

Answer 126

-Many convergent on earlier Allosaurs and Ceratosaurs -Characterized by: – Arctometararsals- metatarsals wrap around each other and are interlocked – Semilunate carpal - relates to their ancestry to birds-relates to how birds come out of this group

Answer 127

- Late Jurassic of Europe - Near-shore islands - “Turkey-sized” - Probably feathered

Answer 128

- Late Cretaceous of Asia and North America, possibly also Australia - Further digit loss – Arm use? - Robust skulls-thick-restist hard forces, protect - Dilong – feathered Tyrannosaur - lots of variation in size-much more diversity in this group that people think! Cuz people usually just think of T rex

Answer 129

- Cretaceous of Laurasia – Possibly also Gondwana - many become omnivorous & herbivorous -so not all theropods are carnivorous! - Some have bizarre osteological adaptations – E.g., Duck-like beaks

Answer 130

- Cretaceous of S. & N. America and Asia - Short, stout forelimbs, with reduced digits-wrist bones fused together, then one huge finger - would use stout fingers to dig up social insects-ants and termites-poke at them and pull out parts-maybe these guys were the anteaters of the Cretaceous - didn’t have much in terms of teeth

Answer 131

-Characters: – Breast bones present in some – In some the pubis faces backward like birds (and ornithischians) -Possibly primitively omnivorous -small -may have evolved flight independently from birds-and in diff way-some had wings on front limb and hindlimb-gliders? -some debate on their relationship to birds-do birds come from this group, or are they a separate group altogether?

Answer 132

smallest dinosaur!

Answer 133

- Late Cretaceous of Asia and N. America - Misidentification of eggs gave them their name-originally thought were stealing eggs, but later realized were sitting on own eggs - Similar to Ornithomimosaurs - reinforced toothless jaws make have been used for crushing hard objects, e.g., clams

Answer 134

-hyper-specialized giant forelimbs -huge gut-digested plants in there, didn’t grind up in mouth -Possibly analogous to giant ground sloths -Cretaceous Laurasian in distribution – Falcarius – from N. Amer. Oldest member of the group

Answer 135

- “Terrible claw” - Late Jurassic to Cretaceous - Some possibly arboreal - Some possibly omnivorous - Group that birds are derived from

Answer 136

Coelophysids and Herrarasaurids

Answer 137

– Laurasia Allosaurs, Compsognathus, Deinonychosaurs Gondwana -Abelisaurs, Ceratosaurs

Answer 138

Laurasia: -Spinosaurs, Allosaurs, Tyrannosaurs, Ornithomimosaurs, Alvarezsaurids, Oviraptors, Therizinosaurs, Deinonychosaurs Gondwana: -Abelisaurs, Ceratorsaurs, Spinosaurs, Ornithomimosaurs (?) Alvarezsaurids (S.A.), Tyrannosaurs (?) -increase in diversity in taxa and ecological groups, land changing, dividing

Answer 139

1) Increase in head size 2) Increase in tooth size. 3) Increase in jaw muscle mass (deeper jaw, larger adductor chamber.) 4) Greater skull rigidity. 5) Reduction in distal elongation.

Answer 140

Whereas Allosaurus may have killed by repeatedly applying relatively weak slashing bites and backing off (killed over time), large tyrannosaurids used more forceful crushing bites-nipping strategy (to get strips of flesh in tight spots) and "puncture and pull" biting - like cats (tigers) and (wild) dogs today - Dogs tend to attack in packs with many small nipping bites that wear down (large) prey (okay that it’s large cuz hunt in packs) - Cats tend to be solitary, and kill with powerful “killing bites” and use their limbs

Answer 141

-nipping strategy )to get strips of flesh in tight spots) and "puncture and pull" biting

Answer 142

ceratopsians and ankylosaurs (3.5-8 tons)

Answer 143

crush, didn't nip

Answer 144

- Pervasive selection for large body size leads to the evolution of hypercarnivory (a diet of large prey) - And this in turn leads to increased vulnerability to extinction. - so as get bigger, eat larger prey-can’t live off little prey anymore cuz can’t get enough of them fast enough-and as get bigger, tend to get smaller population sizes, so more prone to extinction - IF you are carnivorous, and selection favors larger size, THEN ….. energetic constraints will favor adaptations for taking large prey, and …. - These specializations for hypercarnivory and large body size will result in reduced population densities, and vulnerability to extinction. - Evolution of large size and dental specialization leads to a decline in evolutionary versatility (the ability to adapt to new conditions). - EVOLUTION IS NOT PRESCIENT!

Answer 145

1) Predator avoidance-top of food chain, stronger, less predators after you and can defend self well 2) Can kill wider range of prey species. 3) Improved thermal efficiency. 4) Advantageous in interference competition-if you kill something, you get to eat all of it-don’t have to take a piece and run-no one will fight you for it/kick you out-Intraguild predation and carcass theft are significant among big predators. Body size often determines the winner.

Answer 146

other theropods

Answer 147

a) population density will decline, and b) species will become more vulnerable to extinction. -evolution of size leads to decrease in ability to adapt evolution doesn’t care about extinction-just cares about fitness of individual-if bigger, easier to survive-evolution leads to improvement on individual level but extinction on species level

Answer 148

-Estimates done with modeling: – Allosaurus & Tyrannosaurus 4-11m/s (9-25mph) – (Much) faster speeds for smaller taxa -look at modern animalis, mass to speed ratios-then try to do same thing for dinos, use other models to help -t rex was probably not a fast runner-9-25 mph-so fast, but not cheetah fast-fast enough to run down a human at the higher end -smaller dinos probably moved a lot faster

Answer 149

- Relatively small eyes - Enhanced smell(smell rotting animals, draws them in) - Relatively slow speed - Tiny forelimbs - Piercing teeth-for taking off big parts of flesh and crushing bones like modern hyenas

Answer 150

- Large absolute size of eyes even if relatively small for their head - Smell can be used to find living as well as dead - Prey were slow too-so didn’t matter than t rex was slow - Some modern predators don’t have useful arms either – wolves, secretary birds, etc. - Teeth similar to crocodiles - Obligate scavengers (if only eat already dead pray-there’s an energetic cost-have to move around quickly, get to it before competitors, takes a lot of energy-so) need to be soaring vertebrates (i.e., vultures) due to energetic costs - found an animal that was attacked by a T Rex and healed and survived-evidence that T Rex went after living animals

Answer 151

-probably somewhere in the middle-T Rex was the biggest thing around-it’ll eat whatever it wants-probably wasn’t an obligate scavenger but an occassional scavenger

Answer 152

- Behavior probably changed during growth - Younger individuals were smaller and faster - Older individuals were slower and probably ate bigger prey - High mortality among neonates-probably had a lot of offspring, prococious, went out to get prey, but these smaller young were probably prey themselves-so a lot died, but those who survived went to top of the food chain

Answer 153

- May have tracked changes in sea level - Changes in sea level may have led to isolation and migrations-led to speciation - this is what gets done with modern animals esp birds-looking at why so many species, relate to environmental things

Answer 154

-model skulls to look at biting, teeth to look at diet-lots of things going into this, holistic thing-looking at all diff aspects of Tyrannasaurus biology to figure out characteristics

Answer 155

- oviraptor nest with decayed skeletons found - found evidence on bones of animal of flesh-eating beetles-same ones we see today - use now to ready skeletons to get put in museum collections-get rid of all flesh - used for forensic work too-can tell how long it’s been out based on how many life cycles of these beetles have happened

Answer 156

- important cuz drove evolution of sauropods - Pteridophytes - Gymnosperms - Angiosperms

Answer 157

- vascular tissue & spores - Horsetails - Ferns

Answer 158

- naked seed plants (have seeds, but not encased in fruit) - Cycads - Ginkgos - Conifers

Answer 159

- have seeds, but encased in fruit-flowers turn into fruit | - flowering plants

Answer 160

- Develop ‘fruiting body’ that releases spores - Need water to germinate because they have spores - Modern taxa (“Equisetum”) are small - Mesozoic taxa reached 30P (10m) tall - adults don’t really have leaves-young only have thin ones - long, thin, flexible plants - much more diverse group in the pst-much bigger part of ecosystem

Answer 161

-Two stage life-cycle – Sporophyte – gives off spores – Gametophyte – a developing spore -so basically like if egg and sperm left our bodies then lived on own for a while before coming together -Need water to germinate -Tree ferns grew to immense sizes (although not as large today)

Answer 162

-Aka “sego palms” -Dioecious -male and female plants are separate – Male plants give off pollen – Female plants have seeds -Thick leaves to resist predawn -Much more diverse in Mesozoic

Answer 163

- One living species -“Ginkgo biloba” - Dioecious-usually just see the males though? - First ‘woody’ plants - Stinky seeds that “reptiles” like

Answer 164

-Modern cedars, cypresses, firs, junipers, pines, redwoods -Mesozoic podocarps and “monkey puzzle trees” – “Lollipop” morphology – Restricted to southern continents today -some are monoecious (having male and female reproductive structures), some dioecious -now restricted to southern continents, but much more widely spread throughout mesozoic

Answer 165

- Flowering plants - First ones in the early Cretaceous-start to take over by end-but early on, limited -take over because they can grow very quickly-almost like weeds-come in and take over area that’s been recently cleared-so dominant group when you think of plants - Often with male and female reproductive parts in the same flower - Seeds covered by a fruit - Many are faster growing than gymnosperms - rise of Angiosperms coincides with rise in insect pollinators and herbivores

Answer 166

increased for angiosperms-the rest stay about the same-except early vascular plants die out

Answer 167

- Permian (300Ma) forest from China with exquisite preservation - Dominated by tree ferns with taller conifers and sphenophytes - forests looked a lot diff than today

Answer 168

all around these latitude lines (30 degrees north and south)-has to do with air circulation patterns-find diff plant communities today using this same reasoning

Answer 169

- Most of the plant (and dinosaur) diversity is in the midlatitudes (much like today. Equatorial regions more desert-like: hotter and dryer - Due to hothouse conditions and continental position - so we know kinda what the environment looked like back then, how it affected the plants and animals as climate changed - by studying what happened in the past, may be able to get some knowledge of what happens in the future

Answer 170

-The largest vertebrates to walk the Earth! -Originate in South America in the Triassic -First radiation of dinosaurian herbivores – Adapted to eat the tough plants of the midMesozoic (e.g., cycads & conifers) -First extinction of a major dinosaur lineage – the prosauropods -many early forms were still theropod-like -400kg heart!! (about 900 pounds)

Answer 171

the biggest animals that ever lived on land-but they weren't born big

Answer 172

- a lot of diversity | - many early forms (of sauropods) were still theropod-like

Answer 173

don’t need big heads cuz don’t do much chewing or processing in mouth-just using mouths to rip off plant material, swallow whole-then stomach does all the processing-fermentation, gastroliths

Answer 174

-Large nares (nostrils) – Move further posteriorly during their evolution -Teeth built for scraping plants (not chewing) -Two types of teeth – Pencil (diplodocids) – Thick leaf-like (brachiosaurs) – Both probably for puncturing, not grinding -Plant digestion by fermentation and gastroliths

Answer 175

-An adaptation for living in the water? – Probably not – too much pressure on the lungs -maybe they had a trunk? -many taxa that were found had nostrils pushed back, trunk-like structure-so maybe sauropods did have a trunk-not positive -but the problem with this idea is that sauropods wouldn't have sunk

Answer 176

-Elongated necks -From both elongation of cervical vertebrae and increase in number -Also elongate tails -Thermoregulatory? -Herbivory adaptation? so could get at higher trees Neck Posture: -straight up or held parallel to ground? -probably not so upright-side to side, swing head, eat everything in a certain radius-so could get a lot of food -some groups could lift head high -Blood pressure estimates -Computer modeling of neck motions -Probably more side-to-side than up-down in most taxa

Answer 177

- genus of sauropod dinosaur that lived in North America during the Late Jurassic period - range in age from about 154 to 150 million years ago - cervical vertebrae were less elongated and more heavily constructed than those of Diplodocus and the bones of the leg were much stockier despite being longer, implying that Apatosaurus was a more robust animal - The tail was held above the ground during normal locomotion - Like all sauropods, Apatosaurus had only one claw on the forelimbs and three on its hindlimbs. - skull similar to Diplodocus skull - long/big

Answer 178

- genus of diplodocid sauropod dinosaur - double-beamed chevron bones located in the underside of the tail - lived in what is now western North America at the end of the Jurassic Period - classic dinosaur shape, long neck and tail, and four sturdy legs. - For many years, it was the longest dinosaur known. Its great size may have been a deterrent to the predators Allosaurus and Ceratosaurus

Answer 179

-Pneumatized vertebrae-lots of air, open space – Lighten neck (and support?) – Air Sacs? -Neck (nuchal) Ligaments-area for spine to attach?

Answer 180

- different vertebral joints allow for differing range of motion - can compare these dino spines and necks to other animals-to understand how worked - like suspension bridge? long tendon down neck and back that helped keep head up - hydraulic necks-head heads up with air sacs-filled up air spaces with air, like balloon, helped keep head up - but not all had long necks-brachytrachelopan didn't

Answer 181

``` -Short hind limbs – Longer forelimbs in some taxa -Shorter distal elements – Humerus > radius/ulna – Femur > tibia/fibula -Graviportal posture ```

Answer 182

- Graviportal Digitigrade feet - Still on toes, with a foot pad posteriorly - similar to modern elephant feet - Clawed Feet - Enlarged digit 1 on forelimb with claw - Claws on digits 1-3 in hindlimb (in later forms) - forelimb more digitigrade, hindlimb more plantigrade, in both diplodocus and apatosaurus

Answer 183

- use tail as another leg? - probably did not do this-or if did, not often-probably only for sexy time to help keep balance, use claw to hold onto females

Answer 184

- sociality and stance - upright posture as you’d expect from dinos - travelled in groups or herds-shows some sociality

Answer 185

- Worldwide distribution | - 2 major groups: Prosauropods and Sauropods

Answer 186

- Late Triassic – Early Jurassic - First extinction of a major dinosaur lineage - Long, narrow skulls - Serrated, leaf-like teeth - Facultative bipeds – Front limbs shorter than hindlimbs -can walk on 1 or 4 legs - 10 cervical vertebrae - Not as large as later sauropods (2-10m) - necks not very long

Answer 187

- one of the best known dinos-many skeletons found, many complete - a genus of plateosaurid dinosaur that lived during the Late Triassic period, around 214 to 204 million years ago - prosauropod - As of 2011, two species are recognized: the type species P. engelhardti, and the slightly earlier P. gracilis - a bipedal herbivore with a small skull on a long, mobile neck, sharp but plump plant-crushing teeth, powerful hind limbs, short but muscular arms and grasping hands with large claws on three fingers, possibly used for defence and feeding - large variation in size - usually lived 12-20 years - mass death site suggests sociality

Answer 188

``` -Mainly Jurassic – except Titanosaurs that last through Cretaceous, mostly in Gondwana -Enlarged coracoid (on pectoral girdle) -Claws on hind digits 1-3 ->12 cervical vertebrae (necks bigger) -Further elongate tails -More elaborate vertebrae -two major lineages ```

Answer 189

- single nostril opening-nares posterior and between orbits | - procumbent, slender peg-like teeth at anterior margin of mouth

Answer 190

- single nostril opening-nares posterior and between orbits | - procumbent, slender peg-like teeth at anterior margin of mouth

Answer 191

- a giant, long-tailed, long-necked, plant-eating dinosaur closely related to the more familiar Diplodocus. - Upper Jurassic period

Answer 192

- Apatosaurus ajax was named first (by Marsh) - Brontosaurus excelsus was named later (also by Marsh) - Were found to be part of the same genus, and Apatosaurus has priority - when you discover 2 species are actually the same thing, go with older name, forget the newer one

Answer 193

can lift heads higher, cuz have forelimbs on ground, not bipedal

Answer 194

- dermal armor | - why? species recognition thing? don’t really know-interesting

Answer 195

-NE Utah -Jurassic -Specimens of: – Apatosaurus – Barosaurus – Camarasaurus – Diplodocus

Answer 196

-Probably ate lower quality plant material – tough parts of conifers and cycads -Large size may have helped with digesting poor quality plant material -May have prevented overgrazing -Plants adapted to sauropods – Another Red Queen race that drove them to bigger sizes-led to gigantism in sauropods

Answer 197

huge herbivores and conifers dominated the forests. Herbivores created open spaces that favor weedy opportunists (angiosperms)

Answer 198

low browsing herbivores and first angiosperms

Answer 199

diverse low browsing herbivores and diverse angiosperms

Answer 200

1. ‘Bird’ hips (reverse pubis) – possibly to make room for big stomachs 2. Leaf-shaped teeth 3. Lower jaw with predentary bone 4. Network of bony ligaments (called ossified tendons in lab) – stiffen backbone

Answer 201

ornithopods, marginocephalians, thyreophorans

Answer 202

Thyreophorans & Marginocephalians

Answer 203

“Armored Dinosaurs” - Characterized by osteoderms – “skin bones” or scutes - Probably another “Arms Race” with theropods -like when species increase in size-this is another solution, to develop armor - Herbivorous – with some specific adaptations for eating plants (only theropods can be carnivorous-but not all theropods are carnivorous) - Also characterized by post-orbital processes

Answer 204

-Form in the connective tissue layers of the skin -Multiple purposes in thyreoporans – Defense, display (sexual selection or species recognition), thermoregulation (may have helped them regulate body temp) -Also found on titanosaurs (sauropods), other diapsids, and edentate mammals

Answer 205

- Small, leaf-like teeth, inset from the edge of the jaw (probably for cheeks) - but probably didn’t chew a whole lot with this tiny little teeth-mostly just tore stuff up and swallowed - Beaks (rhamphotheca) for nipping plants - Possibly long tongues that could extend to pull of plant material – we think they had this because they had well developed hyoids -bone between voice box and tongue-usually mean attachment for some sort of muscular tongue - Wide thoracic regions-kind of barrel shaped – fermentation vats (for fermentation of plant material)

Answer 206

-most of these guys were quadrupedal (walked on 4 legs) -Large forelimb to hindlimb ratio (1:2)-hindlimbs relatively tall compared to forelimbs – Thickened limbs -Wide stance and slow gait – Possibly semi-sprawling forelimbs -Low browsers-probably kept heads relatively low-couldn’t lift highs very high -but hold tail up a bit, head not completely down

Answer 207

- Mostly Solitary - No ‘mass graves’ - Pinacosaurus burial site in Mongolia is the only site with multiple individuals, including juveniles - so they probably weren’t very common or very social

Answer 208

- Early Jurassic of Laurasia - Possibly bipedal (facultative-could choose to walk on 4 legs or 2 legs?- or obligate) - but eventually this group of dinos had to become quadrupedal so later forms quadrupedal - scutellosaurus (SW USA), scelidosaurus (england)

Answer 209

- an extinct genus of thyreophoran ornithischian dinosaur that lived approximately 196 million years ago during the early part of the Jurassic Period - is classified in Thyreophora, the armoured dinosaurs - bipedal - one of the earliest representatives of the armored dinosaurs and the basalmost form discovered to date - a small, lighly-built, ground-dwelling, herbivore, that could grow up to an estimated 1.175 m (3.9 ft) long

Answer 210

-a genus of herbivorous armoured ornithischian dinosaur from the early Jurassic -known for their excellent preservation. Scelidosaurus has been called the earliest complete dinosaur -Only one species, Scelidosaurus harrisonii, is considered valid today 0about 4 metres (13 ft) long -largely quadrupedal animal, feeding on low scrubby plants, the parts of which were bitten off by the small, elongated, head to be processed in the large gut. -Scelidosaurus was lightly armoured, protected by long horizontal rows of keeled oval scutes, that stretched along the neck, back and tail. -a basal member of the Thyreophora -One of the oldest known and most "primitive" of the thyreophorans

Answer 211

-mid Jurassic – end Cretaceous -5-9m long -Laurasia and Australia – Maybe S. America & Antarctica – Polar specimens known -Conservative body plan– only change in size -Two groups – Ankylosaurids and Nodosaurids – Differ in skull shape and placement of osteodern-but still basically have same body plan

Answer 212

- Broad skulls with armor covering sutures and the supratemporal fenestrae - like had bones in scalp that eventually fused with skull-covered temporal fenestra, diff holes-all these little bones osteoderms fused to the skull

Answer 213

-Teeth have cingula – ridges around the base

Answer 214

- tooting ankylosaurs? - large blood vessels - vocalization? - communication - physiology? temperature regulation - sensory? smelling - weird complicated nostrils-maybe for some sort of mating call?-looks like trumpet where can make noise, modify noises - some people think it was for temperature regulation-work like turbinates in nasal passages - or maybe it was a sensory thing-neuron receptors in there for smelling things - most like vocalization

Answer 215

- Modified Pelves - For bearing weight of armor - Synsacrum (fused vertebrae and pelvis) with horizontal ilium - Closed acetabula (lost hole there that all dinos have) and reduced pubis-so big steel girder pelvic bones fused with vertebrae

Answer 216

- Tail Spikes and Clubs - Made of enlarged osteoderms - Linked tail vertebrae - could swing around - Possibly for display (sexual selection) - Similar to glyptodonts - maybe used for defense-or used for male on male aggression to fight for females

Answer 217

probably, at least the smaller ones could

Answer 218

- Laurasia (mainly China), Africa, Australia - mid Jurassic to mid Cretaceous - 3-9m long - Parasagidal (near the midline) plate-like osteoderms (raised from the skin some)– Also small neck osteoderms - Tiny skulls – EQs similar to sauropods (small area for brains-most of skull not brains but nasal passage and stuff) - Horizontal tail spikes (smaller)

Answer 219

- Alternating arrangement - Possibly thermoregulatory and/or for display-could’ve flushed them with blood (blood vessels there) and changed color-to attract females or warn males - or maybe both (thermal and display)

Answer 220

- late Jurassic of Portugal | - sauropod-mimic stegosaur?

Answer 221

- these 2 groups kind of replace each other - more stegosaurs in the late jurassic - more ankylosaurs in the late Crestaceous - so looks like there was an armored dino niche-only 1 group could really fill it at a time-so don’t have a lot of stegosaurs and ankylosaurs existed at the same time

Answer 222

“Margin Heads” - Relatively numerous in fossil record (at least ceratopsians) - Very endemic – restricted to Laurasian Cretaceous - Taxonomically complex - Taxa are probably “over-split” - they were finding individuals of the same species and naming them diff things-only later this got fixed-but some evidence there were multiple taxa in some cases - still arguments going on about how diverse Marginocephalia was - debate partly cuz no modern analogs of these species today-so difficult

Answer 223

- fossils show problems of oversplitting, and complications of ontogeny - misidentified-turns out triceratops was just older individual of torosaurus - but new research says they may have been diff species

Answer 224

Huge Heads! - Ceratopsians have largest head/body ratio of any terrestrial animal - heads 1/3 of their body size (in adults) - big cuz of the frills that cover neck region and back of head - Formed by parietal & squamosal bones

Answer 225

dental batteries, gastroliths

Answer 226

heterodont dentition

Answer 227

``` facultative bipeds (early) & quadrupedal (late) – Sprawling (on side) or upright (below them) forelimbs? important when thinking about speed -trackways and comparison to modern taxa say upright stance -so could probably run relatively quickly for short bursts ```

Answer 228

-Increases fitness by increasing the number of mates (and therefore offspring and genes in the next generation)

Answer 229

Artiodactyls (horned hoofed mammals)

Answer 230

Bony core with keratin sheath-Permanent (cows, sheep, goats, African antelope)

Answer 231

Bony core with velvet sheath-Shed yearly (deer, elk, moose)

Answer 232

-Used by males for display and in intraspecific fights (over females)

Answer 233

-North America and China, Cretaceous -1-3m long, one 8m species -what’s unique about these guys are their thickened skulls – fused frontals and parietals -huge domes on their heads 9up to 20cm thick! -thickened dome of cranium

Answer 234

-flat-headed (ex: homocephaloids) and dome-headed (ex: pachycephalosaurs)

Answer 235

- Thickened skulls - Scars on skulls -skulls cracked when head butting - Strong neck & vertebral articulations - Biomechanical analysis - Possible sexual dimorphism-females have lower domes, males have bigger domes-speaks to males fighting over females - compared scars in these dino skulls to scars in skulls of modern head-butting animals-the sorts of scars matched

Answer 236

- may have been more of head pushers - a couple of lizards do this - lock heads and push back and forth in some sort of display - hit heads, move back and forth-flank butting * *none of these are mutually exclusive-maybe did a few of these things**

Answer 237

-Late Jurassic (one taxon) to Late Cretaceous of N. America and China – Probably migration from Asia to N. America -5-9m long -Herbivory adaptations: – Rostral bone – Dental batteries– Powerful jaws – Expanded cheek bones -for muscle attachment-so may have had powerful muscles to bite off plant material

Answer 238

- horns and frills for sexual selection and species recognition, not so much defense - one guy looked at where you see injuries on skulls-exactly where would expect if locking horns-not so many scars on nostrils and other areas-mostly on horns

Answer 239

-slightly later form than in last slide -Primitive – facultative biped? – Frill with no horns -frills came before the horn -2.5m -Nest site with juveniles-so social -Sexual dimorphic-starting to see 2 diff forms-1 male, 1 female -Multiple mass burial sites known in Mongolia

Answer 240

- large nose horn - small eye horns - larger nares & frills - e.g. Centrosaurus

Answer 241

- Small nose horn - Large eye horns - Smaller nares & frills - E.g., Triceratops

Answer 242

-No-some centrosaurines had thickened keratin (nail-like) pads instead of central horns

Answer 243

- very very diverse - why do they have this huge diversity? - maybe a bunch were just dff ages of same species-but this doesn’t explain all of it-a lot of real diversity, more than would expect - one explanation is the “species pump"

Answer 244

- big shallow sea that divides west from east - these guys probably lived in the lowlands between the seaway and the mountains - the sea changed sea level-sea level went up and down over cretaceous-cyclical-happened multiple times over Cretaceous - Repeated rise and fall of interior seaway, could have fragmented populations, leading to speciation-the rise and fall of seaway probably isolated species-separating members of same species-evolve separately-once come back together again later, too diff, no longer same species, can’t mate-this happened again and again, leading to lots of speciation and variation - This has been shown for modern animals and glacial advances

Answer 245

warbler birds-during ice ages glaciers advanced down north america then retreated-fragmented these populations of birds, some retreat down to Mexico, or Florida, or the Caribbean-may have been this species pump that generated all this diversity in warblers-and this has been shown as happening for other birds and other mammals too-so the advance of glaciers works in the same way as the advance of seaways did in the past

Answer 246

- social beasts - maybe flooding event, all got buried at once - very social - lived like modern social animals

Answer 247

- T rex bite marks - seratopsian pelvis with t rex teeth embedded in it-unclear if t rex attacked and killed it or scavenged it-cuz unhealed, so animal was killed or already dead, cuz didn’t heal after - evidence of predation

Answer 248

“Bird Feet” -The herding herbivores of the Late Mesozoic – Similar to modern bovids, zebras, etc. – Best record of social structure in dinosaurs -Efficient plant processing – Possibly most efficient chewing system in vertebrates -Bipeds or facultative quadrapeds – Hoofed fingers on forelimbs in some forms – Ossified tail tendons -1-12m long -herbivores -flocks and herds

Answer 249

-Efficient Herbivores -Jaw joint below the tooth row -Dental batteries -Cranial kinesis -“Duck-Bill” – In later forms -Diversification may have been caused by adaptations to new ecosystems -tooth wear is similar to modern ungulates

Answer 250

new ecosystems and population fragmentation

Answer 251

-Safety in numbers

Answer 252

-Early Jurassic of Africa -Heterodont dentition – ‘canines’ similar to mouse deer-didn’t have dental batteries like later forms -Bipedal – Long tails -probably used for balance – Fused distal elements -means they’re running animals -Possibly diggers -robust forearms, may have used front arms for digging -May not be ornithopods, but primitive ornithischians

Answer 253

-Smallest known ornithischian | – 65-75cm

Answer 254

- Mid Jurassic to Late Cretaceous - Paraphyletic grouping of relatively primitive ornithopods - First to show some of the adaptations for efficient herbivory. - Still relatively small (<2m) - Once thought to be arboreal

Answer 255

-Late Jurassic to end Cretaceous -Contains the majority of the ornithopod taxa – Iguanodon – Hadrosaurs – Lambeosaurs -Some forms had elongate neural spines, similar to spinosaurs-display?-thermoregulation? -Many were probably facultative quadrupeds – Dagger thumb on forelimb-unclear what for – Opposable pinky -some had hooves

Answer 256

- “Duck-bills” - Most developed dental batteries - Unguals (hooves) on hind limb - Long forelimbs - rise after the decline of sauropods

Answer 257

- “Hollow-crested” - Large head ornaments - rise after the decline of sauropods

Answer 258

- Attracting a mate - Sexual Selection - Mating - Building Nests & Laying Eggs - Parental Care (if present) - Growth We have evidence for every step in dinosaurs, many of it from ornithopods!

Answer 259

-Often maladaptive structures-makes it harder to fly or run maybe-but trait still exists because for display or something, helps in sexual selection-ex: cresrs -to say something is a secondary sexual characters, have to eliminate other possible uses: -Defense/offense?-that’s a possible use, but not true for all seratopsians-crests hollow -Thermoregulation?-not these guys – Sexual selection(males attracting females)/species recognition? (recognizing another member of your species that you can mate with)-What should we look for to prove this?

Answer 260

- they shouldn't develop until animals are adults (adult features) - there should be sexual dimorphism

Answer 261

traits shouldn’t develop until animals are adults (i.e., when they’re ready to mate) -lambeosaur growth series show that their cranial crests don't develop until adults?-so for sexual selection?

Answer 262

- There should be different forms in the same population - lambeosaur sexual dimorphism - theropod dimorphism: females bigger than males, as w many dinos

Answer 263

-Usually involves male/male competition or female choice -Why are males usually the ones fighting each other, or for the attention of females? – Unequal investment in resources – Eggs are much more costly than sperm – Also, females usually care for the young, so also have to invest resources in that process

Answer 264

-Often sexual selection can push things too far and they can become maladaptive

Answer 265

- ridiculously giant spikes and things-probably sexual selection - may have been the case in some dinos with headgear - crooning headgear - dewlap and head sacs-had head sacs that blew up/inflated to attract mates-colorful sometimes - some of these didn’t fossilize well - also see in mammal groups-elephants to make disturbing calls, fight each other, bite noses

Answer 266

headgear for making mating calls-did study, used CT scans, saw the inflating sacs

Answer 267

- made difficult by the back spikes and giant size - closest modern example are elephants, but still not a good comparison - cloaca kiss-small penis or none-shoot sperm into female’s cloaca

Answer 268

-Cloaca (“Sewer”): posterior opening that serves as the only opening for the intestinal, reproductive, and urinary tracts of certain animal species– one hole for everything -Female lays eggs in water , maybe some sort of nest -Male comes and fertilizes them -Sometimes this is done simultaneously-like frogs -Rarely is fertilization internal-male sperms inserted into female – E.g. sharks

Answer 269

-Fertilization must occur internally – Sperm stored in female after mating-sometimes she can choose sperm wants to use, cuz often fertilized by multiple males – Eggs grow inside female in oviducts -Still have cloaca -Some taxa appose cloaca -Some males have protuberances to facilitate transfer of sperm -Mammals start to divide up the cloaca

Answer 270

-have evidence of male and female t rex-look similar but male has a few extra bones-people think these extra bones for muscles-to help them evert their penis-other species do this (he mentioned which one but I missed it)

Answer 271

– r selection – lots of offspring, little parental investment – K selection – few offspring and lots of parental investment

Answer 272

– Clutch size-how many eggs you have at any one time – Parental care-have little parental care, k has a lot – Growth rates -animals w/o a lot of parental care grow relatively quickly, while w k, grow slowly

Answer 273

-Dinosaur clutches have 2-30 eggs– Similar to birds-birds are more k selective than r selective – Modern large reptiles lay >100 eggs -Eggs produced in two oviducts

Answer 274

- egg laying - female birds have more spongy bone, and this is seen in dinosaurs-why? using the minerals they’d use to make bone, to make eggs instead - see this in dinos too

Answer 275

- Laid eggs in shallow depressions and covered them with vegetation-similar to some modern reptiles like crocs - There is evidence they used the same sites from year to year. see this in modern birds - Embryos indicate the young were able to walk when born-even though small-a little diff from birds - Also known for sauropods and other taxa - when you look at the spacing of the nests-distance between them one hadrosaur away-one adult size apart-space themselves out on landscapes-like modern birds

Answer 276

- sweep out sand/dirt to build nest - sauropods had hind limbs with claws on them-like turtles-use to dig - brooding in theropod dinos-dinos did brood

Answer 277

- crocodilians burt their eggs partially and cover them with vegetation - the warmth of the decomposing vegetation speeds embryo development-so didn’t need to sit on the nest (brood)-but they did guard the nest - Female crocodilians guard their nests, often lying on or near them. - rookeries and site fidelity in modern birds-Anacapa island-go to same spot every year to lay eggs - all of this pointing to dinos being similar to birds and modern reptiles-but more towards birds - nest collectivity

Answer 278

- protection | - adults protect the infants from predators

Answer 279

- Many dinosaur embryos and newborns are known - Herbivores tend to be altricial, Carnivores tend to be precocial - Both are born small and show quick growth rates and allometric changes -changed shape as they grew - dinos grow vastly bigger than size born at-as grow bigger, habitat and where hunt changes-young don’t hunt in same niches as adults - newborns have little extra bump on nose-used to break out of shell when hatching-lost pretty quickly after birth-some dino embryons that show the bump/egg tooth

Answer 280

- Herbivores tend to be altricial (helpless-can’t do much on own) - Carni

Answer 281

-Carnivores tend to be precocial (hunt on own soon after birth-not hunting same things as adult, but can kind of take care of themselves)

Answer 282

-Some nest sites have evidence that young stayed in nests after being born – (fossils of) Larger-sized individuals found in the nests – Broken egg shells -Level of care probably different in different taxa

Answer 283

yes, but not breast feeding-adult goes out, catches food, partially digests, bring back up into mouth, feed to young--that happens with birds, may be the case with dinos

Answer 284

-nice evidence of nest predation-nest found with eggs and snake in it-snake died in the nest, buried by some event

Answer 285

- Dinos had a 3 part growth curve, especially the biggest ones - Maybe there was parental care in the first part of the curve

Answer 286

-Animals don’t live in a biological vacuum -Not all interactions are predator/prey -Dinosaurs are the “charismatic megafauna” of the Mesozoic-They’re popular and consequently get all the attention-dinos get all attention but were small part of ecosystem-many other species, organisms, just not as exciting so get no attention – Similar to large mammals of today and the Pleistocene

Answer 287

– Short-term changes in wind, pressure, temperature, cloud cover, precipitation, etc.

Answer 288

-the long-term average of weather – More stable - deserts are always deserts, with a relatively low rainfall, but at specific times they can get a lot of rain.

Answer 289

- Historical records only go back about 400yrs (longer in some areas) - so use proxy data

Answer 290

Inference from indirect means

Answer 291

– Glacial deposits-glaciers scrape along the ground as move, drop sediment – Leaf shape-leaves in tropical areas diff shapes than in temperate areas-in tropical environment, heart shaped-in temperate, serrated edges – Tree Rings-give us some evidence of how long the growing season was – Oxygen Isotopes-oxygen comes in 2 diff types, one heavier than other, look at balance of those 2 things to look at climates of the past – Others…

Answer 292

-Centered on Four Corners -Geologically stable since the Mesozoic – Upraised in the Cenozoic -Dramatic Geology – Drained by the Colorado River – Arid climate -Site of many of the best North American dinosaur sites – Incl. Dinosaur NM & Cleveland-Lloyd Dino Quarry

Answer 293

-since the mesozoic this area has been relatively stable-not a lot of faulting and burial that may have ruined things-really good place to find dino fossils-also whole rock was pushed up in the cenozoic, so relatively high, not a lot of precipitation, sediment, stays, easier to find dinos

Answer 294

- Equatorial deserts - Large fluctuations in weather due to large continents - Temperatures 7-10 degrees C (13-18 degrees F) hotter than today

Answer 295

-Highlands to the west and east – Due to subduction off the west coast -Wet areas in between, with lakes and rivers draining to the northwest -Deposition of the Chinle Formation

Answer 296

-East-central Arizona -Late Triassic – 225Ma -Chinle Forma-on exposed as badlands -Contains numerous fossil trees, as well as other plant and animal fossils – Many tree fossils are of large conifers

Answer 297

``` -Fundamental units of stratigraphy – Defining cohesive units of sedimentary rocks – Laterally continuous – Subdivided into members – Grouped into groups ```

Answer 298

- Metaposaurs - Therapsids - Sphenodontans - Procolophonids

Answer 299

-Inhabitant of Petrified Forest -Large (3.5m) herbivorous syanpsids-largest herbivore of the time – Permian survivors

Answer 300

- Diptera – flies and mosquitos - Hymenoptera – hornets, bees, wasps, and ants - Coleoptera - beetles

Answer 301

- fleas don't live on scales, but they do live on feathers... - so dinos probably had feathers

Answer 302

-Mainly small, predatory dinosaurs -Coelophysis – most numerous dinosaur fossil – Ghost Ranch Site, NM-mass death-already talked about this -were they cannibals? probably not-already talked about this too-originally thought were, remains of same species in fossil's stomach, but now think it's a different species

Answer 303

-Relatively small parts of ecosystems

Answer 304

– Prosauropods– None in North America, but present on other continents – Small theropods – Coelophysis and other small taxa – Ornithischians – only in South America

Answer 305

-Perhaps dinosaurs had a “key adaptation” that allowed them to diversify and dominate? – Upright walking? – Endothermy? -2 models for dino takeover in triassic-competitive displacement vs. opportunistic-already talked about this-probably by luck mostly, happened to be good conditions for them

Answer 306

- first time dinos really dominating? - Pangea is beginning to break up - Subduction still occurring off the west coast of North America

Answer 307

- Deposition of the Morrison Formation - Western US more arid, with rivers, and accompanying wetlands, draining to the forming inland sea to the northeast - Extensive sand dunes in the Four Corners area - Still “hot house”-hotter than it is today

Answer 308

-Relatively arid grasslands – In Jurassic “grasses” would have been ferns and horsetails -no real grasses, but things filling in the grass low niche -Many riparian strips along waterways, stream beds, supporting thicker vegetation-similar in age to the Solnhofen limestone

Answer 309

- 146-156Ma - Deposited in braided streams, flood plains, swamplands - Similar in age to Solnhofen Limestone - Found throughout the Colorado Plateau and northward into Canada

Answer 310

-NE Utah Morrison Formation -Jurassic -Specimens of: – Apatosaurus – Barosaurus – Camarasaurus – Diplodocus – Stegosaurus – Dryosaurus – Allosaurus – Torvosaurus – Ceratosaurus (last 3 carnivores, the rest herbivores)

Answer 311

-Central UT -Morrison Formation -Species Counts: – 44 Allosaurus – 6 other theropods – 9 sauropods – 5 ornithopods – 4 Stegosaurus -Predator Trap!… or was it a drought assemblage?

Answer 312

-Predator Trap! Locality was in sticky mud near a river bank … or was it a drought assemblage -The bones don’t seem to have been transported or scavenged -Bones are crushed and -Many sub-adult theropods (Allosaurus) represented -May have been a catastrophic drought event at a watering hole -could've been either-mix of both? but probably more latter

Answer 313

frogs, salamanders, turtles, lizards, snakes, small mammals | – Looking more like today at the small end of things

Answer 314

coral reefs, ammonites, sharks, plesiosaurs, icthyosaurs

Answer 315

first birds, both groups of pterosaurs

Answer 316

- Food types can be inferred from tooth wear and energy content - High browsers vs. Low browsers

Answer 317

- Camarasaurus, Brachiosaurus | - ate conifers and cycads

Answer 318

– Diplodocus, Apatosaurus, Stegosaurus, Gargoyleosaurus (ankylosaur) ornithopods (Dryosaurus & Camptosaurus) – Probably also includes young high browsers – Horsetails and low ferns (no grass!)

Answer 319

``` -10kg to 300kg – Koparion (Deinonychosaurid) – Tanycolagreus (Coelosaur) – Stokesosaurus (Coelosaur) – Marshosaurus (Tetanurid) ```

Answer 320

-1000kg to 2000kg – Allosaurus (Allosaurid)-Most numerous taxon – Ceratosaurus (Ceratosaur) – Torvosaurus (Tetanurid) ***Largest taxa are still half the size of T. rex

Answer 321

-Large animals need more food & land, and tend to be at smaller population sizes & densities – Safety mostly from size-so more about finding food than running away (more about getting away for smaller animals)

Answer 322

270 acres (300 football fields

Answer 323

smaller herbivores and juvenile sauropods

Answer 324

- climate | - methane in atmosphere increased as sauropods thrived-contributed to global warming?

Answer 325

• Western US as island ‘continent’ – interior seaway in North America due to high sea levels • Less fluctuation in climate, and stable tropics/subtropics into high latitudes

Answer 326

-Retreat of Interior Seaway connects east & west North America

Answer 327

- Mainly tropical/subtropical | - Many transgressions/regressions of seaway

Answer 328

-South-central Utah -Deposits of: – Chinle Formation – Morrison Formation – Kaiparowits Formation 74-76Ma

Answer 329

- Record of near continuous deposition on the Colorado Plateau from Paleozoic through Mesozoic - Extends from the Grand Canyon to southern Utah

Answer 330

-During Cretaceous -Occupy many habitats and grow relatively quickly -Trees – Beech, maple, oak, magnolia -Still no grasses – Herbaceous shrubs fill ground cover niche -Hops, buttercups, nettles

Answer 331

-Comparison with more northern faunas reveal differences in faunas – Dinosaur Provincial Park Alberta, Canada Over 30 species of dinosaur – none the same as Kaiparowits -Seems contra to large dinosaurs (and large herds of dinosaurs) needing lots of space.

Answer 332

- Some variation in plant communities north and south - dinos as mesotherms - probably needed less space than similar-sized endotherms/as modern herbivores, cuz not full endotherms or ectotherms-somewhere in between - some migration into highlands allowed for some larger ranges

Answer 333

-Changeover in species through time in the Cretaceous -Possibly due to “Species Pump”-like we discussed earlier – Turnover pulses linked to environmental change -Speciation is caused by: – Isolation – Subsequent evolution

Answer 334

- Although different taxa may be present at different times and places, they oren fill the same niches (jobs in the ecosystems) - Example: compare the modern Serengeti and Yellowstone ecosystems

Answer 335

-By the end of the Cretaceous it is the ONLY large predatory dinosaur -Partly due to Evolutionary Ratchet -Partly due to expansion of range – Interior Seaway dries up -Found in every habitat across the Late Cretaceous -but dinosaurs weren't the only predators-crocodilian-like feeding traces found on ornithischian dinos

Answer 336

limited diversity of dinosaurs (mainly coelophysids and prosauropods) arer they replace non-dinosaur taxa

Answer 337

– Increasing diversity dominated by sauropods and mid-sized carnivores – Small animals similar to today-small carnivores?

Answer 338

- increase in diversity, especially in herbivores. | - Increase in size across taxa, except for many small theropods – Rise in angiosperms

Answer 339

their most diverse

Answer 340

abundant, warm, shallow

Answer 341

- are found in marine sediments | - have many adaptations for aquatic life

Answer 342

``` -Modified Skulls – Anapsids or Euryapsids -Large forms may have been endothermic homeotherms – Evidence from isotopes supports this – May have helped them rule the seas! ```

Answer 343

1 hole behind eye

Answer 344

2 holes behind eye

Answer 345

no holes behind the eye-some spices derived from diapsids-lost holes?-some dinos have this

Answer 346

-1 hole behind the eye, but in diff place than synapsids-higher up, oval-these guys derived from diapsids probably-lost bottom hole behind eye-becomes little dent at bottom of skull-emargination-remnant of that hole

Answer 347

- Euryapsids and anapsids | - Carved out area formed perhaps by loss of bony bar beneath lower temporal fenestra

Answer 348

- ichthyosaurs, placodonts, nothosaurs and plesiosaurs, pliosaurs (all “euryapsids”, the latter 3 were sauropterygians) – May represent one or a few separate invasions of the ocean – May or may not be closely related – All died out by the end of the Mesozoic -sea turtles (“anapsids”) – Originated in Late Triassic, became common in Cretaceous

Answer 349

-crocodiles (diapsids—archosaurs) | – Were mostly terrestrial during the Triassic, but many forms were completely marine by Jurassic

Answer 350

mosasaurs (diapsids—lizards) – Died out at the K/T extinction event

Answer 351

- possibly analogous to seals, sea lions, walruses - hands/feet not very modified (webbed, not paddles), ilium not attached to backbone, large upper temporal fenestra; bone lost beneath lower one?, nostril moved back, up to 4m long, shoulder blades and hips beneath body, more robust arms than legs, piscivore dentition (so ate fish) - nothosaurs probably a primitive group for the first venture into the water-there are a few groups that are derived from them

Answer 352

- Medium (2 m) to large (20 m) marine predators-very big - Probably evolved from nothosaurs. - there are transitional forms - better suited to life in the water than nothosaurs. - Could use paddles for forward propulsion and lift (like penguin)-wing like arms - Significant side-to-side motion allowed in neck. - more weight -helps keep them upright in water - nostril, orbit, upper temporal fenestra-then embayment (remnant lower temporal fenestra?) - hips and shoulders well below back - enlarged gastralia (belly ribs) - diving

Answer 353

- bones more uniform in hand/foot, plus extra phalanges for a larger, smaller paddle - they’ve modified pretty much the whole limb-all flattened and shortened

Answer 354

plesiosaur skulls had a huge upper temporal fenestra and pronounced sagittal crest, implying ridiculously strong jaw snapping muscles

Answer 355

- REALLY long neck-probably to help them catch fish - neck was really mobile too (flexible)-don’t have the interlocking vertebrae, vertebrae more flexible, free to move neck more - muscular

Answer 356

tooth form, tooth marks, and gut contents show most plesiosaurs usually ate fish, but some larger species (with bigger heads) ate other marine reptiles

Answer 357

- swallowed stones - had thick gastralia, allowing them to dive down - manatees had thickened ribs for similar reason - probably also for balance, to keep them upright

Answer 358

- plesiosaurs were aquatic, but may have come to land to lay eggs - some creatures in the water stopped laying eggs altogether, started giving birth to live young

Answer 359

the best-adapted reptile swimmers General information: -Up to 2-4 m long. -Common for 155 million years of the Mesozoic. -Had a worldwide distribution. -Many may have been cephalopod prey specialists -Largest forms may have been similar to modern orcas (killer whales) - macropredatory -giant eyes to let as much light as possible when diving very deep-little bones around it to support this eye -may have dove deep (>600 m) -compact fins, thick body, ilium way below back, even head is streamlined, nostril moved back, sclerotic ring (bondy support for eye)

Answer 360

- .....carbonaceous outline in well-preserved specimens - can see outlines of flippers-can see they had a dorsal fin, like dolphins now-flute like tail, similar to sharks-swam similar to sharks-side by side-as opposed to whales that swim up and down-so these guys are more like fish-has to do with reptilian ancestry

Answer 361

- seen in all well-preserved Jurassic-Cretaceous ichthyosaurs - formed from wedge-shaped vertebrae in that part of tail-so it’s 1 side of tail/fin at the end

Answer 362

- gave birth to live young - came out tail first, as in whales - ichthyosaurs probably didn’t come to land at all - fossils found with juvenile coming out of mother-died in the middle of childbirth, then fossilized like that? more likely that died, fell to bottom of ocean, bloated as decomposed-that bloating pushed the dead juvenile young out of birth canal

Answer 363

- Ichthyosaurs may have dove deep (>600 m): - had nostrils, needed to breathe oxygen-so needed to store oxygen like dolphins - Large thick body, barrel shaped chest, provides stores of oxygen-also store oxygen in muscle tissue in abdomen - Outermost layer of ichthyosaur bones spongy and lightweight, as in other divers. - Some show decompression injuries - need to come back up to air very slowly so don’t die from changing in nitrogen levels so quickly-some of these guys have these injuries from this, came up too fast - Streamlined body (convergent with dolphins), allowing for faster descent/ascent and so deeper dives.

Answer 364

- From lizard-like to dolphin-like. - Vertebrae got taller, shorter, and more numerous, making a stiff, tuna-like body. - Less wasted motion so animal is can swim further, and needs to come up for air less frequently - triassic forms were more lizard like, okay swimmers, could only be in shallow water - cretaceous forms more dolphin-like, can dive deep-evolving to fill new niches - better swimmers-using just tail (like whales?) and can move a lot

Answer 365

- gigantic marine lizards of the Cretaceous - Large (up to 12 m long) oceanic reptiles closely related to lizards (and possibly snakes). - Are found in sediments worldwide. - Were the dominant marine reptile in many oceans of the Cretaceous - Some smaller forms may have been freshwater - Note features indicating aquatic life (e.g., hip and shoulder girdle placement) - fins less paddle like - intramandibular joint-allowed them to have a stronger bite

Answer 366

- probably eating some of the shell sephonites?? at the time-squid or octopus that live in a shell-actually have some proof of this-amniote found with mososaur tooth marks - but big enough that they probably ate whatever they wanted: - gut contents of mosasaurs include: large fish, sharks, other mosasaurs, molluscs, an ocean-diving bird, etc. - evidence: healed wound marks on some of these that matched other individuals-indicate they occasionally fought each other

Answer 367

Mosasaurs may have had live birth! | -Live birth evolves over 100 times in reptiles.-so not that strange, happens a lot

Answer 368

- Turtles originate in Triassic, diversify in Cretaceous - Largest turtle ever lived in Cretaceous seas - related/similar to modern snapping turtles?

Answer 369

- from morocco | - giant suction-feeding turtle from the Cretaceous

Answer 370

snapping giant

Answer 371

- Involved broadening of the ribs and vertebrae - Movement of scapula inside the rib cage - shell of the turtle actually ribs, form the shell - Evidence from paleontology, histology, and development-have really good evidence for how it happened now

Answer 372

took the the sea! like Deinosuchus

Answer 373

-no dinos that were aquatic (except maybe Spinosaurus? which we talked about)-but some archosaurs moved to water-like crocodilians

Answer 374

-once in water, fully marine, don’t need to support weight in more cuz in water-so get really big-this happened to crocs too

Answer 375

- huge! - had over 100 teeth, moveable bone at front of snout - 13m long, 2m long skull - estimates of jaw muscles suggest could have taken down a hadrosaur no problem (african crocs can take down zebras in comparison)

Answer 376

large sharks, large predatory fish, etc.

Answer 377

- up to 7m long - chunk of mososaur back sliced off by ginsu shark found - cannot yet distinguish between hunting and scavenging by the ginsu shark

Answer 378

ammonites and nautilus pumped gas into chambers in their shell to control buoyancy at different depths

Answer 379

- Late Triassic - Cretaceous 100 + species. - Wing span 0.5-12 m (most 2-4 m) - Unique features: 1) Short trunk 2) Large head with pointed jaws and teeth 3) Wings supported by elongate 4th digit. 4) 5 long toes on foot with the 5th divergent. 5) Hollow bones. 6) Large brains w/big optic lobes, cerebellum, reduced olfactory lobes.

Answer 380

- A great example of an analogous structure built on a homologous one - diff wings we see in vertebrates: - all have basic forelimb plan-1 bone, 2 bone, little bone, digits - Wings supported by 4th digit. - Wing membrane has stiffening fibers. - Could be folded at shoulder, elbow and wrist-like modern birds

Answer 381

-Flapping (powered) flight -not gliding flight -Flight muscles located ventrally, as in birds -Pterosaurs had massive flight muscles and well-braced shoulders -Most appear to have been superb fliers – Huge sternum, thick humerus = massive flight muscles – Had the lightest skeleton of any vertebrate animal ever – Had large, toughened wing – Shoulder socket faced forward and outward as in birds, allowing great wing flexibility -Larger pterosaurs (e.g., many pterodactyloids) probably soared more than flapped

Answer 382

-Sternum, crests on humerus, and coracoids in pterosaurs as robust as that of birds – Wing shape similar to those of modern soaring birds -probably as good of (or better) flyers as birds

Answer 383

- Thin-walled (~1mm thick in largest specimens), hollow bones in pterosaurs (right) compared to thick walled, marrow-filled bones in mammals (left) - hollow bones Lightened the pterosaur skeleton, making flight easier.

Answer 384

- Rhamphorynchoids | - Pterodactyloids

Answer 385

- mid Triassic to late Jurassic - Smaller – most >1m wingspan - Longer tail, ogen with flange - Small heads - Uniform teeth - Short necks

Answer 386

- Early Jurassic to end Cretaceous - Larger – up to 12m wingspan, most 3-6m - Short/no tail - Large heads with headgear - Few/no teeth - Long necks

Answer 387

Primarily fish eaters (just based on sharp little teeth), some insectivorous, some planctivorous? - diversity in pterosaur feeding types - pterosaur skimmers-possible method of catching fish, skim surface of water with beak while fly - thalassodromeus from Cretaceous maybe did this-lower jaw tapers to a point like modern skimmers? - scavengers?

Answer 388

- maybe had them | - birds use them, so why not pterosaurs?! A nice case of convergence

Answer 389

- diversity in crests - reconstruct shape using fossils, guess on color-but diff colors and shapes - crest function: display? temperature regulation? - probably for display-there’s some evidence of sexual dimorphism - a pterosaur bone may give us an answer-crests found in diff sizes-if changes size as species grows up/diff sizes found, evidence for sexual selection

Answer 390

- not likely | - based on few known pterosaur trackways-front hands on ground, walk sort on all 4s

Answer 391

- pterosaur found in the gut of a velociraptor - pterosaurs as part of a spinosaur diet - rhamphorynchus caught by a fish at Solnhofen

Answer 392

- Extant archosaurs (related to/ derived from extinct dinosaurs) - Endothermic - ORIGIN: Jurassic (208 - 146 MYA)

Answer 393

- loss of teeth | - enlarged brain

Answer 394

- carpometacarpus-fused carpals and metacarpals - fusion of digits I-III - loss of digits IV & V - Furcula (“wishbone”)-fused clavicles

Answer 395

- carpals fused over time | - active research going on on this

Answer 396

- axial skeleton-large sternum with big heel/raised ridge in the middle of it (called kneeled sternum)-that’s for flight muscles - Pygostyle-reduced and fused caudal vertebrae-start to fuse up some of the parts of their axial skeleton-fusion tends to reduce weight - don’t have a bony tail-have a feathery tail

Answer 397

- flight muscles that lift weigh up and down on front - pectorals - then another muscle that goes through pulley system, little hole-attaches to other side of wing-helps bring the wing up - these 2 muscles that help flight both on the front!! - modern bird flight muscles-25-30% bird weight - in modern birds, flight muscles (heavier cuz not fused?) take up a lot of weight, which is why they keep them anterior so not being dragged down-don’t want to be unstable going back and forth as fly

Answer 398

- lost tarsals-fused into tibia or metatarsals - tibiotarsus-fused tibia and tarsals - tarsometatarsus-fused tarsals and metatarsals - loss of digit V - reversed digit 1 -digit 1 points backwards-allows them to perch - reversed pubis - synsacrum-fused sacral vertebrae and pelvis

Answer 399

-feathers more important and complex than we realize fibers hold onto each other-keeps that nice smooth shape-break if try to bend other way -pneumatic bones-bones w air spaces in them-we have this but filled w marrow-filled w ait for them-connected to their entire respiratory system-to make their breathing slightly more efficient

Answer 400

- Pneumatic bones – saurischians - Modified foot – theropods - 3-finger hand – theropods - Furcula – coelurosaurs - Pygostyle - coelurosaurs - Enlarged tibia – maniraptorans - Large brain – maniraptorans - Reverse pelvis - maniraptorans - Feathers – possibly throughout dinosaurs

Answer 401

Yes, they are maniraptorian dinosaurs. (maniraptor-smallest group within dinos-includes dinoneichus-birds are in this group) -birds=dinos has been suggested since Darwin-but really made definitive statement in Dino Renaissance-so know now birds are dinosaurs

Answer 402

- troodontids, dromeosaurids (“raptors!”), velociraptor - Many of these lineages are small, and become smaller over time.-get smaller as get closer to birds-change in physiology that’s happening probably-as get endothermic-if too big, overheat

Answer 403

- Earliest definitive bird-under debate if actually earliest bird, but close enough to be the earliest bird that we can use it as a model - Late Jurassic – 150Ma - Solnhofen Limestone, Germany - 30-50 cm long - some fossils found w/o feathers -thought this was diff species-but later realized same species-at Solnhofen it’s amazing cuz could see feather imprints, preservation so good-in the ones w/o wings feathers probably just decomposed too quickly?

Answer 404

``` Archaeopteryx displays a mix of traditionally avian and dinosaurian characters. Avian: 1) Feathers 2) Wishbone 3) Reverted big toe Dino: 1) Teeth 2) Bony tail 3) Vertical pubis. 4) Separate fingers w/claws 5) Less fusion in limbs. ```

Answer 405

MOSAIC EVOLUTION: evolution of different characters within in a lineage at different rates, hence more as less independently of one another. -probably evolved for different things than later used for-feathers probably not originally evolved for flight but later used to help flight

Answer 406

Capable of powered flight. Feet modified for perching with retroverted hallux, elongate phalanges and claws, and curved claws-still had claws on front legs-strange cuz modern birds don’t have that-what were these guys still using these little claws for on the front limbs?

Answer 407

- hoatzin (from South America) - Juveniles are unable to fly at birth and have 2 wing claws that they use for climbing trees - so maybe archaeopteryx using these claws to climb with forelimbs too, maybe not that good at flight yet

Answer 408

- modern tree-perching and climbing birds have sharply curved claws - claw curvature in archaeopteryx is more similar to that of arboreal (tree-dwelling) birds) - diff uses for forelimb and hindlimb claws-forelimb claws for climbing, hindlimb claws for perching

Answer 409

-Archaeopteryx didn’t have huge heeled sternum modern birds have for flying-so maybe didn’t have particularly strong wing muscles -but there are some other parts of skeleton that are similar to modern birds -deltopectoral crest-so maybe better flight muscles than we may have expected deltopectoral crest in archaeopteryx and modern birds: -for attachment of flight muscles -other attachment site at sternum and/or wishbone in Archaeopteryx so, archaeopteryx may have had larger flight muscles than tiny sternum suggests

Answer 410

Feather asymmetry (like airplane wings-tapers off at end) helps provide lift and so its presence suggests flight.

Answer 411

Feathers clearly derived from reptilian scales Made of same material. Develop in same way. Are homologous. -intermediate forms found in fossils and in modern birds -prominent rachis, interlocked barbules, flat “vane”

Answer 412

- Feathers may have evolved multiple times in different dinosaur lineages - Implies that feathers may not have been first evolved for flight - wings may have evolved for display, sexual selection, thermoregulation, gliding-evolved separately and not for powered flight-but eventually evolved into that - some sort of feathers may have been present in many dinosaurs - in some ways seem like dinos almost prime for dinos

Answer 413

2 sets of wings-gave stability-not powered flight, glided

Answer 414

- Note theropod feathers are symmetrical (similar to non-flight feathers in birds). - So feathers not originally for flight. - Feathers likely evolved initially for heat regulation and/or display for mating. - maybe dinos had feathers at 1 stage of life but not others-like young had feathers then lost them-think happened w T-Rex babies

Answer 415

- usually can only look at shape-but recent research helps tell us color - -melanosomes in the integumentary filaments of the dino Sinosauropteryx - some theropods may have had iridescent feathers-microrapter gui - makes sense that dinos more colorful than we thought in the past - not just lizard colors-more like birds-get more colorful reconstructions now because we know this - don’t always know exact colors of each dino but getting better at it - Due to abundance in color in many species of closest living relative to dinosaurs: birds

Answer 416

very unclear, and so it is probably best not to use feathers as a key character in arguing bird origins.

Answer 417

-Maniraptor theropods were pre-adapted for evolution of flight

Answer 418

they. .. - had feathers - were bipedal - were small (some of them!) - had hollowed bones and enlarged spaces in skull - had long, flexible arms and hands - so they were kind of ready to fly-had adaptations to flight similar to modern birds, even if not originally evolved for flight-had a lot of characters that we associate with flight in birds, but were using them for something else

Answer 419

-ground up hypothesis -Trees Down Hypothesis FALSE DICHOTOMY -New evidence suggest both are partially right. -used wings to help them run well/run uphill, and run up trees, eventually led to flight

Answer 420

Birds evolved from theropods that were terrestrial cursors and wings evolved to assist in insect catching. Primary evidence : no theropods could climb.

Answer 421

Birds evolved from theropods that climbed to avoid predation and forage, and gliding wings evolved for movement between trees. All early birds are arboreal. It is unlikely that wings would evolve in purely terrestrial animals.

Answer 422

-New evidence of arboreal theropods based on hand and foot anatomy. Dromeosaurids such as Bambiraptor, Deinonychus, and Microraptor could probably use their curved claws for climbing.

Answer 423

-New evidence from the study of extant ground birds that demonstrates the advantage of small wings for tree climbing

Answer 424

- “Incipient feathered forelimbs of proto-birds provided the same locomotor advantages for inclined running as are present in extant birds.” (Dial 2003) - The big advantage : improved hindlimb traction for ascent . - WAIR is an intermediate stage allowing arboreality, and leading to the evolution of more sophisticated flight. - this is a good middle ground between the dichotomies-used wings to help them climb trees-intermediate stage between no wings/wings not really used for anything to do with movement/flight and wings used for flight

Answer 425

-Modern juvenile birds can’t fly, but they do use their wings.

Answer 426

- May have been for escape - Earliest birds probably fed on ground or in trees (weren’t good enough at flying yet to catch insects “on the wing”) - Early birds could run away and jump/scramble into trees, glide down to a safer location in order to escape predators

Answer 427

-Killing behavior – Used for stability while grasping prey with enlarged claws-and to hold down prey?

Answer 428

-Microraptor gui

Answer 429

-“Feathered” maniraptoran dinosaurs (Cretaceous) -Archaeopteryx (Jurassic) -Basal bird taxa (all Cretaceous) Confusciusornis Sapeornis Jeholornis Rahonavis -Enantiornithines (Cretaceous). 40+ species. -Ornithurae (early Cretaceous-Recent), 9000 living species.

Answer 430

-From a less arboreal foot and a climbing hand (e.g., Archaeopteryx) to a more arboreal foot and a flying hand (e.g., Sinornis).

Answer 431

-Body size : large crow to sea bird -Advanced characters: no teeth, horny beak, synsacrum, pygostyle, fully reversed hallux, long tail feathers. -Primitive characters : wing retains claws, relatively short wings, hindlimb structure. Confuciusornis, Early Cretaceous, 125 ma, China:

Answer 432

Almost all were perching birds (long toes, curved claws), but at least one may have been a wader. First recognized in 1981 based on metatarsal features. Now defined by suite of shared derived characters

Answer 433

- Much less common in the early Cretaceous than entantornithines, but the only birds to survive the KT boundary. - Many early taxa show adaptations for living in or near water - Includes all modern birds - Advanced in having: 1) Keeled sternum, 2) Strut-like coracoid, 3) Short pygostyle, 4) Completely fused carpometacarpus. - Primitive in having: 1) Teeth (for fish eatong) 2) 2 claws on wing

Answer 434

-increased over time, birds spread quickly

Answer 435

- mostly flightless birds - moas, paracathartes, lithornis, palaeotis, casuarius - emus, kiwis, rheas, ostriches - oldest fossils are from the paleocene and eocene of Europe and NA. Extant forms, tinamous and ratites, only go back to the Miocene. - restricted to southern continents for biogeographic reasons-Gondawanaland - Cretaceous - giant flightless birds that fill this predator niche for a while until get giant mammalian predators, then these birds start to go extinct

Answer 436

- Diatryma, NA and Eur. - closest sister taxa=ducks & fowl - Phorusrhacid birds: Europe, SA, NA. - there were some giant flying predators as well-like this giant hawk that was adapted to eat big flightless birds-went extinct when humans came to Madagascar - ex: Harpagornis - there were some giant flying predators as well-like this giant hawk that was adapted to eat big flightless birds-went extinct when humans came to Madagascar-ex: Teratornis

Answer 437

- bats-but do it differently-evolve to have this leathery wing-holds 4 fingers-the fossil record of bats and transition to bats is awful, compared to transition to birds which has great fossil record, lots of fossils found - wings originating independently have different skeletal structures, revealing tehir convergent evolution - long middle finger holding up wing-but 4 fingers in all, support wing - fossil record of bat is pretty bad-don’t have good documentation of transition to bats/flight - makes sense-they’re small, don’t tend to live in places where fossilize well when die there

Answer 438

-First to look at large- scale trends in marine communities across time -produced graph showing: What does it show? -First, is increasing diversity over the entire Phanerozoic -Reasons for this increasing diversity: – Pull of the recent – Ecological diversification

Answer 439

- Artifactual - sampling and interest bias | - Small part of a much larger problem with paleontology - TAPHONOMY

Answer 440

- Positive feedback - diversity begets diversity – Creation of ‘ ecospace ’ - e.g. tiering within the marine community - Also predator-prey interactions - “escalation” (Vermeij) - so this says that the diversification was real (not result of just more discovered later)

Answer 441

-these are extinction events -EXTINCTION: 5 major ones: -End Ordivician -End Devonian -End Permian ** -The mother of them all - 90% of all species wiped out -End Triassic -End Cretaceous - K/T ** (**=gonna concentrate on these)

Answer 442

- defined end of mesozioc as end of a bunch of species, beginning of a new one-why tend to happen at these boundaries-because we defined boundaries (eras, periods) based on the change in species, diversity at the time, extinction of species, appearance of a new species - so it’s not a coincidence that extinctions happen at these boundaries-they’re how we defined them

Answer 443

– Being global in extent – Affecting marine and terrestrial organisms – Being brief in duration

Answer 444

``` – Major climatic change – Sea level changes – Volcanism – Plate Tectonics – Extraterrestrial (meteors, things that come from outside of the earth and affect earth) ```

Answer 445

-The Paleozoic Era ends with a mass extinction event -Possible Causes – Formation of Pangaea – Marine anoxia: Oxygen levels greatly depleted in oceans (no mixing!)-not same currents as before, not as much mixing of surface water and deep waters, deep waters become anoxic, depleted of oxygen – Sea level falls about 100 meters-probably related to the formation of pangea – Volcanic activity: huge basalt flow in Siberia about 251 Ma -probably a bit of all of these causes-not just 1

Answer 446

- Pangea | - location of fossil deposits that include the PT boundary

Answer 447

- seas teaming with life | - the land was equally diverse

Answer 448

-49% of all marine families -63% of all terrestrial families surviving families squeaked through at low diversity -this can be used to estimate that 80-90% of all marine species were lost

Answer 449

the disturbance of sedimentary deposits by living organisms. For example, worm burrows -see that Permian and Triassic sediment different-less living organisms-proof of the extintion event

Answer 450

- In the marine realm, very fast. In less than 1 million years, about 94 % of the species disappear from this well-studied fossil deposit in China. - maybe many small extinctions around this time that contributed to it, even a little after it continued

Answer 451

- environmental turmoil 1. Oxygen ratios (18O: 16O) indicate an approximate 6oC rise in global temperatures. 2. Carbon isotope ratios reveal a dramatic increase in atmospheric and oceanic 12C levels, suggesting a serious decline in plant productivity.-one of the reasons behind this is that plants tend to use lighter isotopes-basically most carbon is c12, then a little bit of c13- plants tend to use more c12-so if sudden increase in c12, means plants no longer using up that lighter carbon, getting released to environment-suggests there was a big biotic crisis, that a lot of plants died - In nature, most carbon exists as 12C with minor, but detectable amounts of 13C. Ratio of 13C:12C is the same in the oceans and atmosphere. During photosynthesis, plants (including algae) preferentially utilize 12C thus removing it from the ocean-atmosphere system. When they die, burial will continue to sequester the 12C. Consequently, during times of high plant and animal productivity, the 13C:12C ratio will increase. So, the increase in 12C at the PTR boundary suggest a major biotic crisis occurred.

Answer 452

a) Bolide impact? b) lots of volcanism? c) marine regression? - methane hydrates - there's also evidence of a drought at the permian boundary and - runaway greenhouse earth - probably multiple causes

Answer 453

1. Bolide? Doubtful and there is no definitive evidence yet for a bolide impact at or near the PTR boundary. 2. Marine regression? Unlikely. Also, it does not explain terrestrial extinctions and the rapidity of the extinctions. 3. Volcanism : maybe.

Answer 454

- Marine regression (drop in sea level) would remove extensive areas of shallow nearshore environments. (most diversity occurs close to shore) - Less area means increased competition and species extinctions.

Answer 455

- Largest known volcanic eruption. - 2 million km2 of basalt that today cover 1.6 km2 of eastern Russia to a depth of 400-3000 meters. - The eruptions occurred over a span of one million years and have been dated at 251 ma - The Siberian traps are flood basalts: - Flood basalts are thought to result from plumes that rise within the mantle and emerge on the surface in fissures, creating successive layers of lava. - Basically HUGE hot spots!!! that’s burning hole in continental crust-get huge fields of basalt deposited at that time as stuff from the mantle comes up to the surface and spreads out on surface - so could have caused the extinction-evidence that volcanos caused it/for the extinction in general

Answer 456

- Volcanic eruptions produce: ash, CO2, sulfur dioxide, water vapor, and various other gases - this can contribute to global warming, ozone destruction, acid rain, and global cooling - quick cooling (100-1000 years) then warming of the earth-global warming for (1mil years) - So, the Siberian traps probably had a major impact on the earth’s climate and could explain the global warming. - But can they account for the large increase in 12C? - Models say no. Not even in combination with the instantaneous destruction of all life on earth. - so we need another explanation

Answer 457

The melting of methane hydrates (combination of ice and methane). - Methane hydrates are cages of water molecules that surround and trap methane molecules. They freeze under moderate pressures (e.g. > 300 meters below sea level) at temperatures above the freezing point of water. - Global warming could raise sea temperature enough such that these methane hydrates would melt, releasing methane into the water column. - Methane (CH4) will rapidly react with O2 to form CO2 and H2O. - The CO2 will rise to the surface as bubbles and evaporate, raising CO2 levels in the atmosphere. - feedback cycle where gets worse and worse as global warming continues, methane released more, which contributes to more global warming - A runaway release of gas could occur if marine methane hydrates melted and this may be what happened at the PTR boundary. - In the ocean, the release of CO2 also shifts the pH of the water, making it more acidic, and causes calcium carbonate to dissolve, thereby killing a wide variety of marine organisms (corals, all shelled creatures).

Answer 458

- could've contributed to the P/T extinction - massive greenhouse earth led to massive volcanic eruptions, which leads to atmospheric CO2 increase, which leads to global warming on land and sea, which leads to melting of methane hydrates, which leads back to atmospheric CO2 increase, go through cycle again - we worry this will happen to us now, because we have global warming, and methane deposits

Answer 459

- slow - Marine biodiversity at the family level did not reach pre-Triassic levels for 100 myr. Complex ecological structure returned to the oceans within 10 myr. - there's evidence of oxygen-poor water 244 mya - data on the recovery of land are sparse, but new groups replace formerly dominant forms

Answer 460

-Is there a lag in diversity recovery? -How are communities rebuilt? – First back are the low diversity, high abundance, quickly reproducing faunas - “weeds” -Are the most complex forms hit the hardest? (we learned that earlier-as species evolve to be more complex and bigger, more susceptible to extinction) -Importance of refugia - “Lazarus taxa”-species migrate to places where climate change not as bad (where no fossil record available), then come back later-so see them reappear in fossil record

Answer 461

- a few marine reptiles, few dinos (who become birds), and pterosaurs make it out - bees, lizards, snakes, marine species all hit hard, but do make it through

Answer 462

Extraterrestrial Impact!-first proposed in 1980 by Luis Alvarez and colleagues-meteor came to earth, killed most dinos

Answer 463

-Iridium is not very common on earth-common in meteors and things from space -so see this huge spike at K/T boundary-so this is their main line of evidence for a meteor causing the K/T extinction -then looked and found them all over the world -looked for more evidence-wanted to find a crater-and they did-dated it, looked to be right age -Chicxulub Crater was discovered in 1990. 195 km in diameter. -In addition, it was near sediments that indicated a tsunami occurred about the same time, and had lots of glass spherules (droplets of melted earth, pushed up?, solidified in atmosphere, landed on earth) and shocked quartz (only gets formed in high pressure-that you would see formed in an impact) -Fluvial sediments show increased acidity, and there is evidence of global fires -think they may have found a piece of the meteorite too -meteor would’ve set atmosphere on fire-and we have evidence of many forest fires at the time -also would’ve caused tsunamis-we have evidence that there were tsunamis -so looks like this meteor did happen BUT, DID IT KILL THE DINOSAURS? -maybe it wasn’t the impact of the meteor, but other things that contributed to it -also a volcanic event that happened at the time-Deccan traps

Answer 464

1) Dust, smoke, and debris that blocked sunlight for many months; and 2) An instantaneous pulse of thermal energy that ignited many fires - photosynthesis basically stopped at the time - rise in iridium contributes to decline in pollen

Answer 465

-Plants swithch to “weedier” fast growth strategies

Answer 466

- Previously, historical scientists (paleontologists, geologists, etc.) followed a fairly strict uniformitarian stance – the processes happening now were the same in the past. - Catastrophism was associated with deluvian (flood) ideas. - Now we have a Neo-Catastrophist/ Uniformitarian view – allows for unique events in the past (and future) - it’s kind of a combination of the 2 views-uniformitarian but sometimes there are catastrophes

Answer 467

- Indian basalt flows, similar to the Siberian Traps associated with the P/Tr boundary - 2000m thick in some places - Dated to 68.5-66.5Ma - May have contributed to the decline in diversity at K/T boundary

Answer 468

- The bolide impact was the final blow that eliminated dinosaurs, pterosaurs, and others, but all these groups were already in decline due to climate change, sea level fall, and volcanic activity. - There is some evidence that large herbivores were on the decline, which may have made communities more susceptible to large scale changes - but some say that not going extinct before-rapid extinction - signor-lipps effect: since dinos fossilized so rarely, (large dinos) may look like they’re going extinct before they’re actually going extinct-small ones preserved more readily-unlikely to find big dino preserved right at k/t boundary just because not found often but could’ve existed then - so, yes, there may have been some decline going on at the time, but probably not much - so recent research support rapid extinction

Answer 469

the "Age of Mammals" (and Birds)

Answer 470

-Evidence of past life, including body, chemical, and trace fossils. -Includes: – Whole Body Fossils – Preservation of Hard Parts & Petrification – Molds and Casts – Trace fossils – ichnofossils (ichnology) – Chemical traces

Answer 471

the physical and chemical processes that lead to fossilization

Answer 472

-Mummification, frozen & bog specimens, amber

Answer 473

either: - fill up the spaces in the fossil with some mineral - petrification-turn actual substance of species into some rock

Answer 474

-so can make casts and molds from these fossils, preserved as one or the other, but can make the other from it if want to see

Answer 475

-footprints preserved-shoes another animal walked across their path-can tell 1 smaller than another-so probably a pack of female elephants-then a male followed behind-can tell this just by looking at trackways

Answer 476

The study of the processes by which animals become fossilized - composition and decomposition - exposure and weathering - transport and burial - fossilization and exhumation - how well they’re preserved has to do with how fast water flowing, how much exposed, how much energy in environment

Answer 477

- fossil localities with exceptional preservation | - ex: Burgess shale, Solnhofen limestone, Messel Pit, La Brea Tar Pits

Answer 478

- modern day LA - Pleistocene - 4-44 thousand years ago (kya) - Over 4 million plant and animal fossils - More than 600 species - Tar pits acted as a natural trap for large animals - Now the specimens are ‘sub-fossils’, with some of the original material still present-been permeated with asphalt so very dark-could technically get DNA out of them but chemicals you would have to use to get the tar out would get rid of the DNA - in 1914, oil wells filled this entire area-people came to get the oil out-attracted a lot of people, made money off of it

Answer 479

no!! | instead, there are: direwolves, lions, bear, bison, horses, camels, sabertooth tiger

Answer 480

- Broad plains, crisscrossed by rivers from the nearby mountains - Petroleum seeps forming sticky asphalt on the surface, which get covered in water, leaves, & sediment - basic landscape the same as now-not much plate movement - oil forms close to the surface sediment-comes out on the surface-instead of being below rock like it usually is-more oil here than anywhere else-why LA is here-densest oil in the world, not widespread but dense

Answer 481

(prof’s research) - first looked at and took big fossils out to display but didn’t do much research - Reopened in 1969 - 28’ by 28’ square divided into a 3’ by 3’ grid - 6” thick blocks - Extensive data capture on over 18,000 specimens

Answer 482

-Bones are clumped together in the pit -Dating shows episodic capture in the pits – Entrapment rates were about 1 every 50-70yrs, during entrapment episodes -Dates mostly follow Law of Superposition (older things under younger things), although there has been some ‘mixing’ -Further proof of this ‘mixing’ is that few of the specimens are ar;culated – you rarely find skeletons that are put together -What causes this mixing? – Mixing of multiple deposits? – Movement in the deposit? gooey enough that things could move around within – Trampling? did they stay at the surface level and get trampled?

Answer 483

not sure-scavenged, buried? already talked about this

Answer 484

- have an inverted food web distribution - a few prey get captured, many predators come to eat them, killed in trap-so predators more likely to die for once-1 prey can be responsible for the death of many predators

Answer 485

- Herbivores, mainly juveniles, get trapped in the tar - This attracted carnivores, many of which got trapped themselves - Carnivores that didn’t get trapped dragged off half of the carcasses - What was led was quickly buried, with little weathering or abrasion - After burial, fossils were compacted and some mixing occurred

Answer 486

-Why do we find SOME articulated skeletons? -How long does it take for the skeletons to fall apart in the tar? -What causes the mixing? – Trampling? – Settling? – Churning?

Answer 487

- A controlled experiment on carcass decomposition in an actual tar pit-not much evidence for this (prof did this) - got down to bones relatively quickly-why? what does this mean? more research should be done

Answer 488

-Allows us to tell the story of the fossils, from the death of the animal until they were discovered -Based on the study of modern day processes -This can give us insights into – the behavior of the animals – the environment they lived in – the geology of the area

Answer 489

- Mammals are modified reptiles evolved to be endotherms via the concerted evolution of various adaptations - Convergence to repeated forms in different taxonomic groups - Different groups have fossil records of varying quality - Ecological community structure can drive evolution

Answer 490

Three major modern groups : - Monotremes - Marsupials - Placentals

Answer 491

- Hair - Warm-blooded, endotherm, homeothermic - Mammary glands - Live birth (except Monotremes) - but none of these fossilize well-need way to describe mammals when it comes to fossils

Answer 492

- popular in mesothermic-only a few alive today-in Australia | - platypus

Answer 493

- dominant mammal in Australia-exist in South America too - found in Virginia, but much more diverse in other parts of the world - have pouch-young born very very small-grow inside the pouch

Answer 494

- anything you think of as a mammal-bats, whales, etc. (and all the ones seen below, in La Brea Tar Pits) - and some cool carnivores - and humans

Answer 495

- We have to look at their skeletons, specifically, the main character we look for is a lower jaw made of one bone - New jaw joint evolved between dentary bone (lower jaw or mandible) and squamosal bone (on skull) - good fossil record for this - made our jaw stronger-more powerful bites-helped us chew - also helped our hearing-reptiles can’t hear well-we can because of way jaws work

Answer 496

Quadrate => Incus | Articular => Malleus

Answer 497

- "ontogeny recapitulates phylogeny” - said development stages of species reflect its different earlier evolutionary forms-this is kinda true, especially here - bone out then retreat back into ears-see this transition happen in the development of mammals

Answer 498

tympanic membrane to outside

Answer 499

air-filled chamber between the tympanic membrane and inner ear that contains the ossicles

Answer 500

organs of hearing and balance + equilibrium

Answer 501

- to take air vibrations and turn them into fluid vibrations - this ear chamber here is an air dome, connects to back of throat-auditory tube-why ears pop, or can’t hear during cold-yawm or chew, open up tube and ease up pressure there

Answer 502

-It probably has to do with a suite of adaptations – Better hearing-secondarily – Better tooth occlusion for bear chewing-stronger bite – More powerful bites- – Suckling-generate more pressure(?) in mouth for sucking -Most of these things probably had to do with endothermy

Answer 503

-The ability to keep a constant body temperature (unlike reptiles and other lower vertebrates) -Can be active all the time BUT – Leads to increased food requirements, which leads to the need for… -Better food processing, i.e. chewing – Chewing increases rate of digestion and therefore the amount of food that can be eaten per unit time

Answer 504

MAMMALS ARE DIPHYODONT : they have only two sets of teeth, juvenile and adult. (we’ve talked about this)

Answer 505

...precise OCCLUSION (the bringing of opposing surfaces of the teeth of the two jaws into contact, i.e. when lower teeth meet upper teeth as the mouth is closed)

Answer 506

- single rooted - continuously replaced, and - simple pegs that do not occlude precisely - so reptiles don't chew

Answer 507

INCREASED FOOD NEEDS => BETTER CHEWING=> PRECISE OCCLUSION => DIPHYODONTY

Answer 508

...a period of dependency on mom for food, i.e. lactation-since adult teeth haven’t come in as well, can’t chew well-having baby teeth led to having to get food some other easier way-may have led to lactation

Answer 509

- posture - endotherms have a more erect posture-relates to us being able to breathe better-can time breathing to running (if walk on all 4s-humans/bipedal creatures are diff)

Answer 510

semi-erect

Answer 511

...mammals to couple breathing and strides

Answer 512

Mammals also have unique structures in their nose, the turbinates that make their breathing more efficient. FUNCTION OF TURBINATES : 1) CONDITION INCOMING AIR 2) CONSERVE HEAT 3) CONSERVE WATER Because: HIGH VENTILATION RATES* IN ENDOTHERMS CREATE A WATER and HEAT CONSERVATION PROBLEM *Ventilation rate = breaths/minute

Answer 513

endothermy: -leads to fur and hair - also leads to needing more food/oxygen - which leads to needing a stronger bite - leads to new jaw joint - new ear - better locomotor abilities - leads to erect posture - better chewing - diphyodonty - lactation - precise occlusion - more efficient breathing - turbinates

Answer 514

- 1 group leads to dinos, but 1 to mammals | - all of these are amniotes-all derived from this egg-laying amniote-free from water, laid eggs on land

Answer 515

- pelycosaurs - therapsids - cynodonts

Answer 516

- the earliest mammal-like reptiles | - many were carnivorous

Answer 517

giant extinction event, pelycosaurs die out, 1 therapsid group survives (but others die), cynodonts survive and thrive, then mammalia thrives-the others dying out leaves room in niche for mammals

Answer 518

- mammal like reptiles-filled main predator niche - ugly - carnivores and herbivores - herbivore ex: lystrosaurus-important biogeographic indicator that Wegner used in his theory of continental drift-cuz found in Africa-strange - first evidence of respiratory turbinates - starting to look a bit more mammalian, at least in their physiology

Answer 519

- really starting to look like modern mammals - looks like weird mix between tiger and lizard - nice transitional group from reptilian looking things to modern mammals

Answer 520

- 220 mya-Triassic - earliest true mammals that are completely endothermic-they were small-true for dinos too-earliest lineages that lead to birds are small-see this in mammals too - shrew-like

Answer 521

- originally thought possum, shrew-like things, and none larger than a house cat - new research suggests they were more diverse than previously thought, and some bigger than thought - so turns out much more diverse in mesozoic than earlier thought-look more like pictures above-not just little rat-like things running under dino feet - 1 even found w dinosaur remains in stomach - warthog size-bigger

Answer 522

mammals diversify and turn into all the diff groups we see today-really come into their own after dinos die out

Answer 523

a lot of evidence of convergence-similar stuff back then to what see today-filled all the niches that would expect them to fill, that normal, placental mammals fill

Answer 524

has to do with plate tectonics-when marsupials evolved, continents all together, then split apart, marsupials get stuck in australia on our, start to fill niches there-so cause of this convergence we see is because of plate tectonics

Answer 525

- Living Mammals belong to 3 groups - Fossil mammals can be distinguished by their skeletal structure, mainly their jaws and ears - Mammals are evolved from reptiles, and have a number of linked adaptations that allow them to be endothermic - Mammals were around during the reign of the dinosaurs, but many (not all) were small and innocuous. - Mammals radiate (diversify) after dinosaurs disappear - Marsupials show many convergences with placental mammals, due to their being isolated from them and filling the same ecological niches (plate tectonics)

Answer 526

c. endotherm

Answer 527

c. gigantotherm.

Answer 528

d. hypsodonty

Answer 529

a. Their skulls were filled with air sacs.

Answer 530

d. ceratosaurs

Answer 531

d. Sinuses

Answer 532

e. ceratosaurs

Answer 533

d. deinonychosaurs

Answer 534

a. means they were filled with air spaces.

Answer 535

b. diplodocids

Answer 536

c. pteridophytes

Answer 537

d. the fact that all species of ceratopsians had some form of them

Answer 538

d. Scutellosaurus

Answer 539

b. a synsacrum

Answer 540

e. predentary bone

Answer 541

c. they have a restricted geographic distribution.

Answer 542

d. have external fertilization

Answer 543

a. gastroliths

Answer 544

a. r-selected

Answer 545

d. Grand Staircase-Escalante National Monument.

Answer 546

d. Dinosaur National Monument.

Answer 547

d. other (non-dinosaur) archosaurs

Answer 548

a. Wyoming

Answer 549

c. euryapsids

Answer 550

a. Plesiosaurs

Answer 551

c. an elongate 4th digit.

Answer 552

d. coelophysids

Answer 553

d. hollow bones

Answer 554

c. sauropods

Answer 555

d. keeled sterna